Geomass Mediated Carbon Sequestration Material Production Methods and Systems for Practicing the Same

ABSTRACT

Geomass mediated carbon dioxide (CO 2 ) sequestering methods and systems are provided. Aspects of the methods include contacting a gaseous source of CO 2  and an aqueous capture ammonia to produce a CO 2  sequestering product and an aqueous ammonium salt, and then contacting the aqueous ammonium salt liquid with a geomass, e.g., alkaline waste product, to regenerate the aqueous capture ammonia. Also provided are systems configured for carrying out the methods.

CROSS-REFERENCE TO RELATED APPLICATIONS

Pursuant to 35 U.S.C. § 119(e), this application claims priority to thefiling date of U.S. Provisional Application Ser. No. 62/726,225 filed onSep. 1, 2018; the disclosure of which applications is hereinincorporated by reference.

INTRODUCTION

Carbon dioxide (CO₂) is a naturally occurring chemical compound that ispresent in Earth's atmosphere as a gas. Sources of atmospheric CO₂ arevaried, and include humans and other living organisms that produce CO₂in the process of respiration, as well as other naturally occurringsources, such as volcanoes, hot springs, and geysers.

Additional major sources of atmospheric CO₂ include industrial plants.Many types of industrial plants (including cement plants, refineries,steel mills and power plants) combust various carbon-based fuels, suchas fossil fuels and syngases. Fossil fuels that are employed includecoal, natural gas, oil, petroleum coke and biofuels. Fuels are alsoderived from tar sands, oil shale, coal liquids, and coal gasificationand biofuels that are made via syngas.

The environmental effects of CO₂ are of significant interest. CO₂ iscommonly viewed as a greenhouse gas. The phrase “global warming” is usedto refer to observed and continuing rise in the average temperature ofEarth's atmosphere and oceans since the late 19th century. Because humanactivities since the industrial revolution have rapidly increasedconcentrations of atmospheric CO₂, anthropogenic CO₂ has been implicatedin global warming and climate change, as well as increasing oceanicbicarbonate concentration. Ocean uptake of fossil fuel CO₂ is nowproceeding at about 1 million metric tons of CO₂ per hour. Since theearly 20th century, the Earth's mean surface temperature has increasedby about 0.8° C. (1.4° F.), with about two-thirds of the increaseoccurring since 1980.

The effects of global warming on the environment and for human life arenumerous and varied. Some effects of recent climate change may alreadybe occurring. Rising sea levels, glacier retreat, Arctic shrinkage, andaltered patterns of agriculture are cited as direct consequences, butpredictions for secondary and regional effects include extreme weatherevents, an expansion of tropical diseases, changes in the timing ofseasonal patterns in ecosystems, and drastic economic impact.

Projected climate changes due to global warming have the potential tolead to future large-scale and possibly irreversible effects atcontinental and global scales. The likelihood, magnitude, and timing isuncertain and controversial, but some examples of projected climatechanges include significant slowing of the ocean circulation thattransports warm water to the North Atlantic, large reductions in theGreenland and Western Antarctic Ice Sheets, accelerated global warmingdue to carbon cycle feedbacks in the terrestrial biosphere, and releasesof terrestrial carbon from permafrost regions and methane from hydratesin coastal sediments.

While a matter of scientific debate, it is believed that excessatmospheric CO₂ is a significant contributing factor to global warming.Since the beginning of the Industrial Revolution, the concentration ofCO₂ has increased by about 100 parts-per-million (ppm) (i.e., from 280ppm to 380 ppm), and was recently observed to reach an average dailyvalue of over 400 ppm. As such, there is great interest in thesequestration of CO₂, particularly in a manner sufficient to at leastameliorate the ever-increasing amounts of anthropogenic CO₂ that ispresent in the atmosphere.

Concerns over anthropogenic climate change and ocean acidification, havefueled an urgency to discover scalable, cost effective, methods ofcarbon capture and sequestration (CCS). Typically, methods of CCSseparate pure CO₂ from complex flue streams, compress the purified CO₂,and finally inject it into underground saline reservoirs for geologicsequestration. These multiple steps are very energy and capitalintensive. Carbonate mineralization is another method to sequester largeamounts of CO₂, in gigaton (Gt, i.e., 1,000,000,000 tons) volumes,sustainably.

SUMMARY

Geomass mediated carbon dioxide (CO₂) sequestering methods and systemsare provided. Aspects of the methods include contacting a gaseous sourceof CO₂ and an aqueous capture ammonia to produce a CO₂ sequesteringproduct and an aqueous ammonium salt, and then contacting the aqueousammonium salt liquid with a geomass, e.g., alkaline waste product, toregenerate the aqueous capture ammonia. Also provided are systemsconfigured for carrying out the methods.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 provides a schematic representation of a system according to anembodiment of the invention.

FIG. 2 provides a schematic representation of a system according to anembodiment of the invention, where CO₂ sequestering carbonate productiontakes place in the presence of an additive, and the aqueous captureliquid regeneration module is driven by renewable energy.

FIG. 3 provides a schematic representation of a system according to anembodiment of the invention, where additional CO₂ gas is coming from theCO₂ sequestering carbonate production module and is recovered bycondensed fugitive ammonia vapor coming from the CO₂ gas/aqueous captureliquid module, and the aqueous capture liquid regeneration module isdriven by waste heat from process steam condensate.

FIG. 4 provides a schematic representation of a system according to anembodiment of the invention.

FIG. 5 provides a schematic representation of a system according to anembodiment of the invention, where the system does not include astripper or other ammonia purification module.

DETAILED DESCRIPTION

Geomass mediated carbon dioxide (CO₂) sequestering methods and systemsare provided. Aspects of the methods include contacting a gaseous sourceof CO₂ and an aqueous capture ammonia to produce a CO₂ sequesteringproduct and an aqueous ammonium salt, and then contacting the aqueousammonium salt liquid with a geomass, e.g., alkaline waste product, toregenerate the aqueous capture ammonia. Also provided are systemsconfigured for carrying out the methods.

Before the present invention is described in greater detail, it is to beunderstood that this invention is not limited to particular embodimentsdescribed, as such may, of course, vary. It is also to be understoodthat the terminology used herein is for the purpose of describingparticular embodiments only, and is not intended to be limiting, sincethe scope of the present invention will be limited only by the appendedclaims.

Where a range of values is provided, it is understood that eachintervening value, to the tenth of the unit of the lower limit unlessthe context clearly dictates otherwise, between the upper and lowerlimit of that range and any other stated or intervening value in thatstated range, is encompassed within the invention. The upper and lowerlimits of these smaller ranges may independently be included in thesmaller ranges and are also encompassed within the invention, subject toany specifically excluded limit in the stated range. Where the statedrange includes one or both of the limits, ranges excluding either orboth of those included limits are also included in the invention.

Certain ranges are presented herein with numerical values being precededby the term “about.” The term “about” is used herein to provide literalsupport for the exact number that it precedes, as well as a number thatis near to or approximately the number that the term precedes. Indetermining whether a number is near to or approximately a specificallyrecited number, the near or approximating unrecited number may be anumber which, in the context in which it is presented, provides thesubstantial equivalent of the specifically recited number.

Unless defined otherwise, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. Although any methods andmaterials similar or equivalent to those described herein can also beused in the practice or testing of the present invention, representativeillustrative methods and materials are now described.

All publications and patents cited in this specification are hereinincorporated by reference as if each individual publication or patentwere specifically and individually indicated to be incorporated byreference and are incorporated herein by reference to disclose anddescribe the methods and/or materials in connection with which thepublications are cited. The citation of any publication is for itsdisclosure prior to the filing date and should not be construed as anadmission that the present invention is not entitled to antedate suchpublication by virtue of prior invention. Further, the dates ofpublication provided may be different from the actual publication dateswhich may need to be independently confirmed.

It is noted that, as used herein and in the appended claims, thesingular forms “a”, “an”, and “the” include plural referents unless thecontext clearly dictates otherwise. It is further noted that the claimsmay be drafted to exclude any optional element. As such, this statementis intended to serve as antecedent basis for use of such exclusiveterminology as “solely,” “only” and the like in connection with therecitation of claim elements, or use of a “negative” limitation.

As will be apparent to those of skill in the art upon reading thisdisclosure, each of the individual embodiments described and illustratedherein has discrete components and features which may be readilyseparated from or combined with the features of any of the other severalembodiments without departing from the scope or spirit of the presentinvention. Any recited method can be carried out in the order of eventsrecited or in any other order which is logically possible.

While the apparatus and method has or will be described for the sake ofgrammatical fluidity with functional explanations, it is to be expresslyunderstood that the claims, unless expressly formulated under 35 U.S.C.§ 112, are not to be construed as necessarily limited in any way by theconstruction of “means” or “steps” limitations, but are to be accordedthe full scope of the meaning and equivalents of the definition providedby the claims under the judicial doctrine of equivalents, and in thecase where the claims are expressly formulated under 35 U.S.C. § 112 areto be accorded full statutory equivalents under 35 U.S.C. § 112.

Methods

As summarized above, aspects of the invention include methods of usinggeomass, such as alkaline waste products, to produce carbon dioxide(CO₂) sequestering material. Accordingly, aspects of the inventioninclude CO₂ sequestration processes, i.e., processes (methods,protocols, etc.) that result in CO₂ sequestration. By “CO₂sequestration” is meant the removal or segregation of an amount of CO₂from an environment, such as the Earth's atmosphere or a gaseous wastestream produced by an industrial plant, so that some or all of the CO₂is no longer present in the environment from which it has been removed.CO₂ sequestering methods of the invention sequester CO₂ by producing asolid storage stable CO₂ sequestering product from an amount of CO₂,such that the CO₂ is sequestered. The solid storage stable CO₂sequestering product is a storage stable composition that incorporatesan amount of CO₂ into a storage stable form, such as an above-groundstorage or underwater storage stable form, so that the CO₂ is no longerpresent as, or available to be, a gas in the atmosphere. Sequestering ofCO₂ according to methods of the invention allows for long-term storageof CO₂ in a manner such that CO₂ does not become part of the atmosphere.

As summarized above, aspects of the methods include: contacting agaseous source of CO₂ and an aqueous capture ammonia to produce a CO₂sequestering product and an aqueous ammonium salt, and then contactingthe aqueous ammonium salt with a geomass, e.g., alkaline waste product,to regenerate the aqueous capture ammonia. Each of these aspects of themethods is now further described in greater detail.

CO₂ Capture

Embodiments of the methods include contacting an aqueous capture liquid,such as an aqueous capture ammonia, with a gaseous source of CO₂ (i.e.,a CO₂ containing gas) under conditions sufficient to produce an aqueouscarbonate liquid, such as an aqueous ammonium carbonate.

The gaseous source of CO₂, i.e., the CO₂ containing gas, may be pure CO₂or be combined with one or more other gasses and/or particulatecomponents, depending upon the source, e.g., it may be a multi-componentgas (i.e., a multi-component gaseous stream). In certain embodiments,the CO₂ containing gas is obtained from an industrial plant, e.g., wherethe CO₂ containing gas is a waste feed from an industrial plant.Industrial plants from which the CO₂ containing gas may be obtained,e.g., as a waste feed from the industrial plant, may vary. Industrialplants of interest include, but are not limited to, power plants andindustrial product manufacturing plants, such as, but not limited to,chemical and mechanical processing plants, refineries, cement plants,steel plants, etc., as well as other industrial plants that produce CO₂as a byproduct of fuel combustion or other processing step (such ascalcination by a cement plant). Waste feeds of interest include gaseousstreams that are produced by an industrial plant, for example as asecondary or incidental product, of a process carried out by theindustrial plant.

Of interest in certain embodiments are waste streams produced byindustrial plants that combust fossil fuels, e.g., coal, oil, naturalgas, as well as man-made fuel products of naturally occurring organicfuel deposits, such as but not limited to tar sands, heavy oil, oilshale, etc. In certain embodiments, power plants are pulverized coalpower plants, supercritical coal power plants, mass burn coal powerplants, fluidized bed coal power plants, gas or oil-fired boiler andsteam turbine power plants, gas or oil-fired boiler simple cycle gasturbine power plants, and gas or oil-fired boiler combined cycle gasturbine power plants. Of interest in certain embodiments are wastestreams produced by power plants that combust syngas, i.e., gas that isproduced by the gasification of organic matter, e.g., coal, biomass,etc., where in certain embodiments such plants are integratedgasification combined cycle (IGCC) plants. Of interest in certainembodiments are waste streams produced by Heat Recovery Steam Generator(HRSG) plants. Waste streams of interest also include waste streamsproduced by cement plants. Cement plants whose waste streams may beemployed in methods of the invention include both wet process and dryprocess plants, which plants may employ shaft kilns or rotary kilns, andmay include pre-calciners. Each of these types of industrial plants mayburn a single fuel, or may burn two or more fuels sequentially orsimultaneously. A waste stream of interest is industrial plant exhaustgas, e.g., a flue gas. By “flue gas” is meant a gas that is obtainedfrom the products of combustion from burning a fossil or biomass fuelthat are then directed to the smokestack, also known as the flue of anindustrial plant.

Waste streams produced by cement plants are also suitable for systemsand methods of the invention. Cement plant waste streams include wastestreams from both wet process and dry process plants, which plants mayemploy shaft kilns or rotary kilns, and may include pre-calciners. Theseindustrial plants may each burn a single fuel, or may burn two or morefuels sequentially or simultaneously. Other industrial plants such assmelters and refineries are also useful sources of waste streams thatinclude carbon dioxide.

Industrial waste gas streams may contain carbon dioxide as the primarynon-air derived component, or may, especially in the case of coal-firedpower plants, contain additional components (which may be collectivelyreferred to as non-CO₂ pollutants) such as nitrogen oxides (NOx), sulfuroxides (SOx), and one or more additional gases.

Additional gases and other components may include CO, mercury and otherheavy metals, and dust particles (e.g., from calcining and combustionprocesses). Additional non-CO₂ pollutant components in the gas streammay also include halides such as hydrogen chloride and hydrogenfluoride; particulate matter such as fly ash, dusts, and metalsincluding arsenic, beryllium, boron, cadmium, chromium, chromium VI,cobalt, lead, manganese, mercury, molybdenum, selenium, strontium,thallium, and vanadium; and organics such as hydrocarbons, dioxins, andPAH compounds. Suitable gaseous waste streams that may be treated have,in some embodiments, CO₂ present in amounts of 200 ppm to 1,000,000 ppm;or 200 ppm to 500,000 ppm; or 200 ppm to 100,000 ppm; or 200 ppm to10,000; or 200 ppm to 5,000 ppm; or 200 ppm to 2000 ppm; or 200 ppm to1000 ppm; or 200 to 500 ppm; or 500 ppm to 1,000,000 ppm; or 500 ppm to500,000 ppm; or 500 ppm to 100,000 ppm; or 500 ppm to 10,000; or 500 ppmto 5,000 ppm; or 500 ppm to 2000 ppm; or 500 ppm to 1000 ppm; or 1000ppm to 1,000,000 ppm; or 1000 ppm to 500,000 ppm; or 1000 ppm to 100,000ppm; or 1000 ppm to 10,000; or 1000 ppm to 5,000 ppm; or 1000 ppm to2000 ppm; or 2000 ppm to 1,000,000 ppm; or 2000 ppm to 500,000 ppm; or2000 ppm to 100,000 ppm; or 2000 ppm to 10,000; or 2000 ppm to 5,000ppm; or 2000 ppm to 3000 ppm; or 5000 ppm to 1,000,000 ppm; or 5000 ppmto 500,000 ppm; or 5000 ppm to 100,000 ppm; or 5000 ppm to 10,000; or10,000 ppm to 1,000,000 ppm; or 10.00 ppm to 500,000 ppm; or 10,000 ppmto 100,000 ppm; or 50,000 ppm to 1,000,000 ppm; or 50,000 ppm to 500,000ppm; or 50,000 ppm to 100,000 ppm; or 100,000 ppm to 1,000,000 ppm; or100,000 ppm to 500,000 ppm; or 200,000 ppm to 1000 ppm, including200,000 ppm to 2000 ppm, for example 180,000 ppm to 2000 ppm, or 180,000ppm to 5000 ppm, also including 180,000 ppm to 10,000 ppm.

The waste streams, particularly various waste streams of combustion gas,may include one or more additional non-CO₂ components, for example only,water, NOx (mononitrogen oxides: NO and NO₂), SOx (monosulfur oxides:SO, SO₂ and SO₃), VOC (volatile organic compounds), heavy metals suchas, but not limited to, mercury, and particulate matter (particles ofsolid or liquid suspended in a gas). Flue gas temperature may also vary.In some embodiments, the temperature of the flue gas comprising CO₂ isfrom 0° C. to 2000° C., or 0° C. to 1000° C., or 0.degree ° C. to 500°C., or 0° C. to 100° C., or 0° C. to 50° C., or 10° C. to 2000° C., or10° C. to 1000° C., or 10° C. to 500° C., or 10° C. to 100° C., or 10°C. to 50° C., or 50° C. to 2000° C., or 50° C. to 1000° C., or 50° C. to500° C., or 50° C. to 100° C., or 100° C. to 2000° C., or 100° C. to1000° C., or 100° C. to 500° C., or 500° C. to 2000° C., or 500° C. to1000° C., or 500° C. to 800° C., or such as from 60° C. to 700° C., andincluding 100° C. to 400° C.

In some instances, the gaseous source of CO₂ is air and product gasproduced by a direct air capture (DAC) system. DAC systems are a classof technologies capable of separating carbon dioxide CO₂ directly fromambient air. A DAC system is any system that captures CO₂ directly fromair and generates a product gas that includes CO₂ at a higherconcentration than that of the air that is input into the DAC system.The concentration of CO₂ in the air that is input to the DAC system mayvary as CO₂ concentrations in the Earth's atmosphere are nothomogeneous. In some instances 100 ppm or greater, such as 500 ppm orgreater, including 5,000 ppm or greater, such that the location of theDAC system is more efficient at CO₂ capture in locations where CO₂concentrations are relatively high, e.g., near congested freewayinterchanges, bad commute corridors, in industrial zones of metropolitanareas and the like. While the concentration of CO₂ in the DAC generatedgaseous source of CO₂ may vary, in some instances the concentration1,000 ppm or greater, such as 10,000 ppm or greater, including 100,000ppm or greater, where the product gas may not be pure CO₂, such that insome instances the product gas is 3% or more non-CO₂ constituents, suchas 5% or more non-CO₂ constituents, including 10% or more non-CO₂constituents. Non-CO₂ constituents that may be present in the productstream may be constituents that originate in the input air and/or fromthe DAC system. In some instances, the concentration of CO₂ in the DACproduct gas ranges from 1,000 to 999,000 ppm, such as 1,000 to 10,000ppm, or 10,000 to 100,000 ppm or 100,000 to 999,000 ppm. DAC generatedgaseous streams have, in some embodiments, CO₂ present in amounts of 200ppm to 1,000,000 ppm; or 200 ppm to 500,000 ppm; or 200 ppm to 100,000ppm; or 200 ppm to 10,000; or 200 ppm to 5,000 ppm; or 200 ppm to 2,000ppm; or 200 ppm to 1,000 ppm; or 200 to 500 ppm; or 500 ppm to 1,000,000ppm; or 500 ppm to 500,000 ppm; or 500 ppm to 100,000 ppm; or 500 ppm to10,000; or 500 ppm to 5,000 ppm; or 500 ppm to 2,000 ppm; or 500 ppm to1,000 ppm; or 1,000 ppm to 1,000,000 ppm; or 1,000 ppm to 500,000 ppm;or 1,000 ppm to 100,000 ppm; or 1,000 ppm to 10,000; or 1,000 ppm to5,000 ppm; or 1,000 ppm to 2,000 ppm; or 2,000 ppm to 1,000,000 ppm; or2,000 ppm to 500,000 ppm; or 2,000 ppm to 100,000 ppm; or 2,000 ppm to10,000; or 2,000 ppm to 5,000 ppm; or 2,000 ppm to 3,000 ppm; or 5,000ppm to 1,000,000 ppm; or 5,000 ppm to 500,000 ppm; or 5,000 ppm to100,000 ppm; or 5,000 ppm to 10,000; or 10,000 ppm to 1,000,000 ppm; or10.00 ppm to 500,000 ppm; or 10,000 ppm to 100,000 ppm; or 50,000 ppm to1,000,000 ppm; or 50,000 ppm to 500,000 ppm; or 50,000 ppm to 100,000ppm; or 100,000 ppm to 1,000,000 ppm; or 100,000 ppm to 500,000 ppm; or200,000 ppm to 1000 ppm, including 200,000 ppm to 2,000 ppm, for example180,000 ppm to 2,000 ppm, or 180,000 ppm to 5,000 ppm, also including180,000 ppm to 10,000 ppm. The DAC product gas that is contacted withthe aqueous capture liquid may be produced by any convenient DAC system.DAC systems are systems that extract CO₂ from the air using media thatbinds to CO₂ but not to other atmospheric chemicals (such as nitrogenand oxygen). As air passes over the CO₂ binding medium, CO₂ “sticks” tothe binding medium. In response to a stimulus, e.g., heat, humidity,etc., the bound CO₂ may then be released from the binding mediumresulting the production of a gaseous CO₂ containing product. DACsystems of interest include alkaline based systems, but are not limitedto: amine based or hydroxide-based systems; CO₂ sorbent/temperatureswing based systems, and CO₂ sorbent/temperature swing based systems. Insome instances, the DAC system is an amine based or a hydroxide basedsystem, in which CO₂ is separated from air by contacting the air with anaqueous amine or an aqueous hydroxide liquid to produce an aqueouscarbonate, such as an aqueous ammonium carbonate. Examples of hydroxidebased DAC systems include, but are not limited to, those described inPCT published application Nos. WO/2009/155539; WO/2010/022339;WO/2013/036859; and WO/2013/120024; the disclosures of which are hereinincorporated by reference. In some instances, the DAC system is a CO₂sorbent based system, in which CO₂ is separated from air by contactingthe air with sorbent, such as an amine sorbent, followed by release ofthe sorbent captured CO₂ by subjecting the sorbent to one or morestimuli, e.g., change in temperature, change in humidity, etc. Examplesof such DAC systems include, but are not limited to, those described inPCT published application Nos. WO/2005/108297; WO/2006/009600;WO/2006/023743; WO/2006/036396; WO/2006/084008; WO/2007/016271;WO/2007/114991; WO/2008/042919; WO/2008/061210; WO/2008/131132;WO/2008/144708; WO/2009/061836; WO/2009/067625; WO/2009/105566;WO/2009/149292; WO/2010/019600; WO/2010/022399; WO/2010/107942;WO/2011/011740; WO/2011/137398; WO/2012/106703; WO/2013/028688;WO/2013/075981; WO/2013/166432; WO/2014/170184; WO/2015/103401;WO/2015/185434; WO/2016/005226; WO/2016/037668; WO/2016/162022;WO/2016/164563; WO/2016/161998; WO/2017/184652; and WO/2017/009241; thedisclosures of which are herein incorporated by reference.

As summarized above, an aqueous capture liquid is contacted with thegaseous source of CO₂ under conditions sufficient to produce a CO₂sequestering material. The CO₂ sequestering material may be producedfrom the gaseous source of CO₂ and capture liquid by using a multistepor single step protocol, as desired. For example, in some embodiments,combination of the CO₂ capture liquid and gaseous source of CO₂ resultsin production of an aqueous carbonate, which aqueous carbonate is thensubsequently contacted with a divalent cation source, e.g., a Ca²⁺and/or Mg²⁺ source, to produce the CO₂ sequestering material. In yetother embodiments, a one-step CO₂ gas absorption carbonate precipitationprotocol is employed.

The concentration of ammonia in the aqueous capture ammonia may vary,where in some instances the aqueous capture ammonia includes ammonia(NH₃) at a concentration ranging from 0.1 to 20.0 moles per liter (M),and in some instances 0.1 to 5.0 M, such as 0.1 to 4.0 M, e.g., 4.0 M,while in other instances from 2 to 20 M, such as 4 to 20 M. The aqueouscapture ammonia may include any convenient water. Waters of interestfrom which the aqueous capture ammonia may be produced include, but arenot limited to, freshwaters, seawaters, brine waters, produced watersand waste waters. In some instances the water of interest may berecycled water from a wastewater treatment plant, wherein the recycledwater already includes NH₃ at a concentration ranging from 10 to 500ppm, and in some instances 10 to 100 ppm, such as 10 to 90 ppm, while inother instances from 100 to 500 ppm, such as from 150 to 500 ppm NH₃.The pH of the aqueous capture ammonia may vary, ranging in someinstances from 10.0 to 13.5, such as 10.0 to 13.0, including 10.5 to12.5. Further details regarding aqueous capture ammonias of interest areprovided in PCT published application No. WO/2017/165849; the disclosureof which is herein incorporated by reference.

The CO₂ containing gas, e.g., as described above, may be contacted withthe aqueous capture liquid, e.g., aqueous capture ammonia, using anyconvenient protocol. For example, contact protocols of interest include,but are not limited to: direct contacting protocols, e.g., bubbling thegas through a volume of the aqueous medium, concurrent contactingprotocols, i.e., contact between unidirectionally flowing gaseous andliquid phase streams, countercurrent protocols, i.e., contact betweenoppositely flowing gaseous and liquid phase streams, and the like.Contact may be accomplished through use of infusers, bubblers, fluidicVenturi reactors, spargers, gas filters, sprays, trays, scrubbers,absorbers or packed column reactors, and the like, as may be convenient.In some instances, the contacting protocol may use a conventionalabsorber or an absorber froth column, such as those described in U.S.Pat. Nos. 7,854,791; 6,872,240; and 6,616,733; and in US PatentApplication Publication US/2012/0237420; the disclosures of which areherein incorporated by reference. The process may be a batch orcontinuous process.

In some instances, the gaseous source of CO₂ is contacted with theliquid using a microporous membrane contactor. Microporous membranecontactors of interest include a microporous membrane present in asuitable housing, where the housing includes a gas inlet and a liquidinlet, as well a gas outlet and a liquid outlet. The contactor isconfigured so that the gas and liquid contact opposite sides of themembrane in a manner such that molecule may dissolve into the liquidfrom the gas via the pores of the microporous membrane. The membrane maybe configured in any convenient format, where in some instances themembrane is configured in a hollow fiber format. Hollow fiber membranereactor formats which may be employed include, but are not limited to,those described in U.S. Pat. Nos. 7,264,725 and 5,695,545; thedisclosures of which are herein incorporated by reference. In someinstances, the microporous hollow fiber membrane contactor that isemployed is a Liqui-Cel® hollow fiber membrane contactor (available from3M Company), which membrane contactors include polypropylene membranecontactors and polyolefin membrane contactors.

Contact between the capture liquid and the CO₂-containing gas occursunder conditions such that a substantial portion of the CO₂ present inthe CO₂-containing gas goes into solution, e.g., to produce bicarbonateions. By substantial portion is meant 10% or more, such as 50% or more,including 80% or more.

The temperature of the capture liquid that is contacted with theCO₂-containing gas may vary. In some instances, the temperature rangesfrom −1.4 to 100° C., such as 20 to 80° C. and including 40 to 70° C. Insome instances, the temperature may range from −1.4 to 50° C. or higher,such as from −1.1 to 45° C. or higher. In some instances, coolertemperatures are employed, where such temperatures may range from −1.4to 4° C., such as −1.1 to 0° C. In some instances, warmer temperaturesare employed. For example, the temperature of the capture liquid in someinstances may be 25° C. or higher, such as 30° C. or higher, and may insome embodiments range from 25 to 50° C., such as 30 to 40° C.

The CO₂-containing gas and the capture liquid are contacted at apressure suitable for production of a desired CO₂ charged liquid. Insome instances, the pressure of the contact conditions is selected toprovide for optimal CO₂ absorption, where such pressures may range from1 ATM to 100 ATM, such as 1 to 50 ATM, e.g., 20-30 ATM or 1 ATM to 10ATM. Where contact occurs at a location that is naturally at 1 ATM, thepressure may be increased to the desired pressure using any convenientprotocol. In some instances, contact occurs where the optimal pressureis present, e.g., at a location under the surface of a body of water,such as an ocean or sea.

Contact is carried out in manner sufficient to produce an aqueousammonium carbonate. The aqueous ammonium carbonate may vary, where insome instances the aqueous ammonium carbonate comprises at least one ofammonium carbonate and ammonium bicarbonate and in some instancescomprises both ammonium carbonate and ammonium bicarbonate. The aqueousammonium bicarbonate may be viewed as a dissolved inorganic carbon (DIC)containing liquid. As such, in charging the aqueous capture ammonia withCO₂, a DAC generated CO₂ containing gas may be contacted with CO₂capture liquid under conditions sufficient to produce DIC in the CO₂capture liquid, i.e., to produce a DIC containing liquid. The DIC is thesum of the concentrations of inorganic carbon species in a solution,represented by the equation: DIC=[CO₂*]+[HCO₃ ⁻]+[CO₃ ²⁻], where [CO₂*]is the sum of carbon dioxide ([CO₂]) and carbonic acid ([H₂CO₃])concentrations, [HCO₃-] is the bicarbonate concentration (which includesammonium bicarbonate) and [CO₃ ²⁻] is the carbonate concentration (whichincludes ammonium carbonate) in the solution. The DIC of the aqueousmedia may vary, and in some instances may be 5,000 ppm carbon orgreater, such as 10,000 ppm carbon or greater, including 15,000 ppmcarbon or greater. In some instances, the DIC of the aqueous media mayrange from 5,000 to 50,000 ppm carbon, such as 7,500 to 15,000 ppmcarbon, including 8,000 to 12,000 ppm carbon. The amount of CO₂dissolved in the liquid may vary, and in some instances ranges from 0.05to 40 mM, such as 1 to 35 mM, including 25 to 30 mM. The pH of theresultant DIC containing liquid may vary, ranging in some instances from4 to 12, such as 6 to 11 and including 7 to 10, e.g., 8 to 8.5.

Where desired, the CO₂ containing gas is contacted with the captureliquid in the presence of a catalyst (i.e., an absorption catalyst,either hetero- or homogeneous in nature) that mediates the conversion ofCO₂ to bicarbonate. Of interest as absorption catalysts are catalyststhat, at pH levels ranging from 8 to 10, increase the rate of productionof bicarbonate ions from dissolved CO₂. The magnitude of the rateincrease (e.g., as compared to control in which the catalyst is notpresent) may vary, and in some instances is 2-fold or greater, such as5-fold or greater, e.g., 10-fold or greater, as compared to a suitablecontrol. Further details regarding examples of suitable catalysts forsuch embodiments are found in U.S. Pat. No. 9,707,513, the disclosure ofwhich is herein incorporated by reference.

In some embodiments, the resultant aqueous ammonium carbonate is a twophase liquid which includes droplets of a liquid condensed phase (LCP)in a bulk liquid, e.g., bulk solution. By “liquid condensed phase” or“LCP” is meant a phase of a liquid solution which includes bicarbonateions wherein the concentration of bicarbonate ions is higher in the LCPphase than in the surrounding, bulk liquid. LCP droplets arecharacterized by the presence of a meta-stable bicarbonate-rich liquidprecursor phase in which bicarbonate ions associate into condensedconcentrations exceeding that of the bulk solution and are present in anon-crystalline solution state. The LCP contains all of the componentsfound in the bulk solution that is outside of the interface. However,the concentration of the bicarbonate ions is higher than in the bulksolution. In those situations where LCP droplets are present, the LCPand bulk solution may each contain ion-pairs and pre-nucleation clusters(PNCs). When present, the ions remain in their respective phases forlong periods of time, as compared to ion-pairs and PNCs in solution.Further details regarding LCP containing liquids are provided in U.S.Pat. No. 9,707,513, the disclosure of which is herein incorporated byreference.

Production of Solid CO₂ Sequestering Carbonate

As reviewed above, both multistep and single step protocols may beemployed to produce the CO₂ sequestering carbonate material from the CO₂containing gas the aqueous capture ammonia. For example, in someembodiments the product aqueous ammonium carbonate is forwarded to a CO₂sequestering carbonate production module, where divalent cations, e.g.,Ca²⁺ and/or Mg²⁺, are combined with the aqueous ammonium carbonate toproduce the CO₂ sequestering carbonate. In yet other instances, aqueouscapture ammonia includes a source of divalent cations, e.g., Ca²⁺ and/orMg²⁺, such that aqueous ammonium carbonate combines withe divalentcations as it is produced to result in production of a CO₂ sequesteringcarbonate.

Accordingly, in some embodiments, following production of an aqueouscarbonate, such as an aqueous ammonium carbonate, e.g., as describedabove, the aqueous carbonate is subsequently combined with a cationsource under conditions sufficient to produce a solid CO₂ sequesteringcarbonate. Cations of different valances can form solid carbonatecompositions (e.g., in the form of carbonate minerals). In someinstances, monovalent cations, such as sodium and potassium cations, maybe employed. In other instances, divalent cations, such as alkalineearth metal cations, e.g., calcium (Ca²⁺) and magnesium (Mg²⁺) cations,may be employed. When cations are added to the aqueous carbonate,precipitation of carbonate solids, such as amorphous calcium carbonate(CaCO₃) when the divalent cations include Ca²⁺, may be produced with astoichiometric ratio of one carbonate-species ion per cation.

Any convenient cation source may be employed in such instances. Cationsources of interest include, but are not limited to, the brine fromwater processing facilities such as sea water desalination plants,brackish water desalination plants, groundwater recovery facilities,wastewater facilities, blowdown water from facilities with coolingtowers, and the like, which produce a concentrated stream of solutionhigh in cation contents. Also of interest as cation sources arenaturally occurring sources, such as but not limited to native seawaterand geological brines, which may have varying cation concentrations andmay also provide a ready source of cations to trigger the production ofcarbonate solids from the aqueous ammonium carbonate. In some instances,the cation source may be a waste product of another step of the process,e.g., a calcium salt (such as CaCl₂) produced during regeneration ofammonia from the aqueous ammonium salt.

In yet other embodiments, the aqueous capture ammonia includes cations,e.g., as described above. The cations may be provided in the aqueouscapture ammonia using any convenient protocol. In some instances, thecations present in the aqueous capture ammonia are derived from ageomass used in regeneration of the aqueous capture ammonia from anaqueous ammonium salt. In addition and/or alternatively, the cations maybe provided by combining an aqueous capture ammonia with a cationsource, e.g., as described above.

The product CO₂ sequestering carbonate compositions produced byembodiments of methods of the invention may vary greatly. Theprecipitated product may include one or more different carbonatecompounds, such as two or more different carbonate compounds, e.g.,three or more different carbonate compounds, five or more differentcarbonate compounds, etc., including non-distinct, amorphous carbonatecompounds. Carbonate compounds of precipitated products of the inventionmay be compounds having a molecular formulation X_(m)(CO₃)_(n) where Xis any element or combination of elements that can chemically bond witha carbonate group or its multiple, wherein X is in certain embodimentsan alkaline earth metal and not an alkali metal; wherein m and n arestoichiometric positive integers. These carbonate compounds may have amolecular formula of X_(m)(CO₃)_(n).H₂O, where there are one or morestructural waters in the molecular formula. The amount of carbonate inthe product, as determined by coulometry using the protocol described ascoulometric titration or by loss on ignition (LOI) using the standardtest methods for LOI of solid combustion residues per ASTM D7348, may be40% or higher, such as 70% or higher, including 80% or higher.

The carbonate compounds of the precipitated products may include anumber of different cations, such as but not limited to ionic speciesof: calcium, magnesium, sodium, potassium, sulfur, boron, silicon,strontium, and combinations thereof. Of interest are carbonate compoundsof divalent metal cations, such as calcium and magnesium carbonatecompounds. Specific carbonate compounds of interest include, but are notlimited to: calcium carbonate minerals, magnesium carbonate minerals andcalcium magnesium carbonate minerals. Calcium carbonate minerals ofinterest include, but are not limited to: calcite (CaCO₃), aragonite(CaCO₃), vaterite (CaCO₃), ikaite (CaCO₃.6H₂O), and amorphous calciumcarbonate (CaCO₃). Magnesium carbonate minerals of interest include, butare not limited to magnesite (MgCO₃), barringtonite (MgCO₃.2H₂O),nesquehonite (MgCO₃.3H₂O), lanfordite (MgCO₃.5H₂O), hydromagnesite, andamorphous magnesium calcium carbonate (MgCO₃). Calcium magnesiumcarbonate minerals of interest include, but are not limited to dolomite(CaMg)(CO₃)₂), huntite (Mg₃Ca(CO₃)₄) and sergeevite (Ca₂Mg(CO₃)₁₃.H₂O).The carbonate compounds of the product may include one or more waters ofhydration, or may be anhydrous. In some instances, the amount by weightof magnesium carbonate compounds in the precipitate exceeds the amountby weight of calcium carbonate compounds in the precipitate. Forexample, the amount by weight of magnesium carbonate compounds in theprecipitate may exceed the amount by weight calcium carbonate compoundsin the precipitate by 5% or more, such as 10% or more, 15% or more, 20%or more, 25% or more, 30% or more. In some instances, the weight ratioof magnesium carbonate compounds to calcium carbonate compounds in theprecipitate ranges from 1.5-5 to 1, such as 2-4 to 1 including 2-3 to 1.In some instances, the precipitated product may include hydroxides, suchas divalent metal ion hydroxides, e.g., calcium and/or magnesiumhydroxides.

Further details regarding carbonate production and methods of using thecarbonated produced thereby are provided in: U.S. application Ser. No.14/204,994 published as US-2014-0322803-A1; 14/214,129 published as US2014-0271440 A1; Ser. No. 14/861,996 published as US 2016-0082387 A1; aswell as U.S. Pat. Nos. 9,707,513; 9,714,406 and 9,993,799; thedisclosures of which are herein incorporated by reference.

In some instances, carbonate production occurs in a continuous fashion,e.g., as described in U.S. Pat. No. 9,993,799, the disclosure of whichis herein incorporated by reference. In some such instances, carbonateproduction may occur in the presence of a seed structure. By seedstructure is meant a solid structure or material that is present flowingliquid, e.g., in the material production zone, prior to divalent cationintroduction into the liquid. By “in association with” is meant that thematerial is produced on at least one of a surface of or in a depression,e.g., a pore, crevice, etc., of the seed structure. In such instances, acomposite structure of the carbonate material and the seed structure isproduced. In some instances, the product carbonate material coats aportion, if not all of, the surface of a seed structure, e.g., acarbonate coated seed structure. In some instances, the productcarbonate materials fills in a depression of the seed structure, e.g., apore, crevice, fissure, etc.

Seed structures may vary widely as desired. The term “seed structure” isused to describe any object upon and/or in which the product carbonatematerial forms. Seed structures may range from singular objects orparticulate compositions, as desired. Where the seed structure is asingular object, it may have a variety of different shapes, which may beregular or irregular, and a variety of different dimensions. Shapes ofinterest include, but are not limited to, rods, meshes, blocks, etc.Also of interest are particulate compositions, e.g., granularcompositions, made up of a plurality of particles. Where the seedstructure is a particulate composition, the dimensions of particles mayvary, ranging in some instances from 0.01 to 1,000,000 μm, such as 0.1to 100,000 μm.

The seed structure may be made up of any convenient material ormaterials. Materials of interest include both carbonate materials, suchas described above, as well as non-carbonate materials. The seedstructures may be naturally occurring, e.g., naturally occurring sands,shell fragments from oyster shells or other carbonate skeletalallochems, gravels, etc., or man-made, such as pulverized rocks, groundblast furnace slag, fly ash, cement kiln dust, red mud, returnedconcrete, recycled concrete, demolished concrete and the like. Forexample, the seed structure may be a granular composition, such as sand,which is coated with the carbonate material during the process, e.g., awhite carbonate material or colored carbonate material, e.g., asdescribed above.

In some instances, seed structure may be coarse aggregates, such asfriable Pleistocene coral rock, e.g., as may be obtained from tropicalareas (e.g., Florida) that are too weak to serve as aggregate forconcrete. In this case the friable coral rock can be used as a seed, andthe solid CO₂ sequestering carbonate mineral may be deposited in theinternal pores, making the coarse aggregate suitable for use inconcrete, allowing it to pass the Los Angeles abrasion test per AASHTO96 and ASTMs C131 or C535. In some instances, where a lightweightaggregate is desired, the outer surface will only be penetrated by thesolution of deposition, leaving the inner core relatively ‘hollow’making a light weight aggregate for use in light weight concrete.

Production of Materials from the CO₂ Sequestering Carbonate Product

The product carbonate material may be further used, manipulated and/orcombined with other compositions to produce a variety of end-usematerials. In certain embodiments, the product carbonate composition isrefined (i.e., processed) in some manner. Refinement may include avariety of different protocols. In certain embodiments, the product issubjected to mechanical refinement, e.g., grinding, in order to obtain aproduct with desired physical properties, e.g., particle size, etc. Incertain embodiments, the product is combined with a hydraulic cement,e.g., as a sand, a gravel, as an aggregate, etc., e.g., to produce finalproduct, e.g., concrete or mortar.

Also of interest are formed building materials. The formed buildingmaterials of the invention may vary greatly. By “formed” is meantshaped, e.g., molded, cast, cut or otherwise produced, into a man-madestructure defined physical shape, i.e., configuration. Formed buildingmaterials are distinct from amorphous building materials, e.g.,particulate (such as powder) compositions that do not have a defined andstable shape, but instead conform to the container in which they areheld, e.g., a bag or other container. Illustrative formed buildingmaterials include, but are not limited to: bricks; boards; conduits;beams; basins; columns; drywalls etc. Further examples and detailsregarding formed building materials include those described in U.S. Pat.No. 7,771,684; the disclosure of which is herein incorporated byreference.

Also of interest are non-cementitious manufactured items that includethe product of the invention as a component. Non-cementitiousmanufactured items of the invention may vary greatly. Bynon-cementitious is meant that the compositions are not hydrauliccements. As such, the compositions are not dried compositions that, whencombined with a setting fluid, such as water, set to produce a stableproduct. Illustrative compositions include, but are not limited to:paper products; polymeric products; lubricants; asphalt products;paints; personal care products, such as cosmetics, toothpastes,deodorants, soaps and shampoos; human ingestible products, includingboth liquids and solids; agricultural products, such as soil amendmentproducts and animal feeds; etc. Further examples and detailsnon-cementitious manufactured items include those described in U.S. Pat.No. 7,829,053; the disclosure of which is herein incorporated byreference.

Aggregates

As summarized above, the methods and systems of the invention may beemployed to produce carbonate coated seed structures, e.g., carbonatecoated aggregates or, optionally without a seed structure, e.g., purecarbonate aggregates, rocks, etc., for use in concretes and otherapplications. The carbonate coated aggregates may be conventional orlightweight aggregates.

Aspects of the invention include CO₂ sequestering aggregatecompositions. The CO₂ sequestering aggregate compositions includeaggregate particles having a core and a CO₂ sequestering carbonatecoating on at least a portion of a surface of the core. The CO₂sequestering carbonate coating is made up of a CO₂ sequesteringcarbonate material, e.g., as described above. The CO₂ sequesteringcarbonate material that is present in coatings of the coated particlesof the subject aggregate compositions may vary. In some instances, theisotopic profile of the core of the aggregate differs from the carbonatecoating of the aggregate, such that the aggregate has a carbonatecoating with a first isotopic profile and a core with a second isotopicprofile that is different from the first.

In some instances, the carbonate material is a highly reflectivemicrocrystalline/amorphous carbonate material. Themicrocrystalline/amorphous materials present in coatings of theinvention may be highly reflective. As the materials may be highlyreflective, the coatings that include the same may have a high totalsurface reflectance (TSR) value. TSR may be determined using anyconvenient protocol, such as ASTM E1918 Standard Test Method forMeasuring Solar Reflectance of Horizontal and Low-Sloped Surfaces in theField (see also R. Levinson, H. Akbari, P. Berdahl, Measuring solarreflectance—Part II: review of practical methods, LBNL 2010). In someinstances, the backsheets exhibit a TSR value ranging from Rg; 0=0.0 toRg; 0,=1.0, such as Rg; 0,=0.25 to Rg; 0,=0.99, including Rg; 0,=0.40 toRg; 0,=0.98, e.g., as measured using the protocol referenced above.

In some instances, the coatings that include the carbonate materials arehighly reflective of near infrared (NIR) light, ranging in someinstances from 10 to 99%, such as 50 to 99%. By NIR light is meant lighthaving a wavelength ranging from 700 nanometers (nm) to 2.5 millimeters(mm). NIR reflectance may be determined using any convenient protocol,such as ASTM C1371 Standard Test Method for Determination of Emittanceof Materials Near Room Temperature Using Portable Emissometers or ASTMG173 Standard Tables for Reference Solar Spectral Irradiances: DirectNormal and Hemispherical on 37° Tilted Surface. In some instances, thecoatings exhibit a NIR reflectance value ranging from Rg; 0=0.0 to Rg;0=1.0, such as Rg; 0=0.25 to Rg; 0=0.99, including Rg; 0=0.40 to Rg;0=0.98, e.g., as measured using the protocol referenced above.

In some instances, the carbonate coatings are highly reflective ofultraviolet (UV) light, ranging in some instances from 10 to 99%, suchas 50 to 99%. By UV light is meant light having a wavelength rangingfrom 400 nm and 10 nm. UV reflectance may be determined using anyconvenient protocol, such as ASTM G173 referenced above. In someinstances, the materials exhibit a UV value ranging from Rg; 0=0.0 toRg; 0=1.0, such as Rg; 0=0.25 to Rg; 0=0.99, including Rg; 0=0.4 to Rg;0=0.98, e.g., as measured using the protocol referenced above.

In some instances, the coatings are reflective of visible light, e.g.,where reflectivity of visible light may vary, ranging in some instancesfrom 10 to 99%, such as 10 to 90%. By visible light is meant lighthaving a wavelength ranging from 380 nm to 740 nm. Visible lightreflectance properties may be determined using any convenient protocol,such as ASTM G173 referenced above. In some instances, the coatingsexhibit a visible light reflectance value ranging from Rg; 0=0.0 to Rg;0=1.0, such as Rg; 0=0.25 to Rg; 0=0.99, including Rg; 0=0.4 to Rg;0=0.98, e.g., as measured using the protocol referenced above.

The materials making up the carbonate components are, in some instances,amorphous or microcrystalline. Where the materials are microcrystalline,the crystal size, e.g., as determined using the Scherrer equationapplied to the FWHM of X-ray diffraction pattern, is small, and in someinstances is 1,000 microns (μm) or less in diameter, such as 100 micronsor less in diameter, and including 10 microns or less in diameter. Insome instances, the crystal size ranges in diameter from 1,000 μm to0.001 μm, such as 10 to 0.001 μm, including 1 to 0.001 μm. In someinstances, the crystal size is chosen in view of the wavelength(s) oflight that are to be reflected. For example, where light in the visiblespectrum is to be reflected, the crystal size range of the materials maybe selected to be less than one-half the “to be reflected” range, so asto give rise to photonic band gap. For example, where the to bereflected wavelength range of light is 100 to 1,000 nm, the crystal sizeof the material may be selected to be 50 nm or less, such as rangingfrom 1 to 50 nm, e.g., 5 to 25 nm. In some embodiments, the materialsproduced by methods of the invention may include rod-shaped crystals andamorphous solids. The rod-shaped crystals may vary in structure, and incertain embodiments have length to diameter ratio ranging from 500 to 1,such as 10 to 1. In certain embodiments, the length of the crystalsranges from 0.5 μm to 500 μm, such as from 5 μm to 100 μm. In yet otherembodiments, substantially completely amorphous solids are produced.

The density, porosity, and permeability of the coating materials mayvary according to the application. With respect to density, while thedensity of the material may vary, in some instances the density rangesfrom 5 g/cm³ to 0.01 g/cm³, such as 3 g/cm³ to 0.3 g/cm³ and including2.7 g/cm³ to 0.4 g/cm³. With respect to porosity, as determined by GasSurface Adsorption as determined by the BET method (Brown Emmett Teller(e.g., as described in S. Brunauer, P. H. Emmett and E. Teller, J. Am.Chem. Soc., 1938, 60, 309. doi:10.1021/ja01269a023) the porosity mayrange in some instances from 100 m²/g to 0.1 m²/g, such as 60 m²/g to 1m²/g and including 40 m²/g to 1.5 m²/g. With respect to permeability, insome instances the permeability of the material may range from 0.1 to100 darcies, such as 1 to 10 darcies, including 1 to 5 darcies (e.g., asdetermined using the protocol described in H. Darcy, Les FontainesPubliques de la Ville de Dijon, Dalmont, Paris (1856)). Permeability mayalso be characterized by evaluating water absorption of the material. Asdetermined by water absorption protocol, e.g., the water absorption ofthe material ranges, in some embodiments, from 0 to 25%, such as 1 to15% and including from 2 to 9%.

The hardness of the materials may also vary. In some instances, thematerials exhibit a Mohs hardness of 3 or greater, such as 5 or greater,including 6 or greater, where the hardness ranges in some instances from3 to 8, such as 4 to 7 and including 5 to 6 Mohs (e.g., as determinedusing the protocol described in American Federation of MineralogicalSocieties. “Mohs Scale of Mineral Hardness”). Hardness may also berepresented in terms of tensile strength, e.g., as determined using theprotocol described in ASTM C1167. In some such instances, the materialmay exhibit a compressive strength of 100 to 3,000 N, such as 400 to2,000 N, including 500 to 1,800 N.

In some embodiments, the carbonate material includes one or morecontaminants predicted not to leach into the environment by one or moretests selected from the group consisting of Toxicity CharacteristicLeaching Procedure (TCLP), Extraction Procedure Toxicity Test, SyntheticPrecipitation Leaching Procedure, California Waste Extraction Test,Soluble Threshold Limit Concentration, American Society for Testing andMaterials Extraction Test, and Multiple Extraction Procedure. Tests andcombinations of tests may be chosen depending upon likely contaminantsand storage conditions of the composition. For example, in someembodiments, the composition may include As, Cd, Cr, Hg, and Pb (orproducts thereof), each of which might be found in a waste gas stream ofa CO₂ emitter, such as in the flue gas of a coal-fired power plant.Since TCLP tests for As, Ba, Cd, Cr, Pb, Hg, Se, and Ag, TCLP may be anappropriate test for aggregates described herein. In some embodiments, acarbonate composition of the invention includes As, wherein thecomposition is predicted not to leach As into the environment. Forexample, a TCLP extract of the composition may provide less than 5.0mg/L As indicating that the composition is not hazardous with respect toAs. In some embodiments, a carbonate composition of the inventionincludes Cd, wherein the composition is predicted not to leach Cd intothe environment. For example, a TCLP extract of the composition mayprovide less than 1.0 mg/L Cd indicating that the composition is nothazardous with respect to Cd. In some embodiments, a carbonatecomposition of the invention includes Cr, wherein the composition ispredicted not to leach Cr into the environment. For example, a TCLPextract of the composition may provide less than 5.0 mg/L Cr indicatingthat the composition is not hazardous with respect to Cr. In someembodiments, a carbonate composition of the invention includes Hg,wherein the composition is predicted not to leach Hg into theenvironment. For example, a TCLP extract of the composition may provideless than 0.2 mg/L Hg indicating that the composition is not hazardouswith respect to Hg. In some embodiments, a carbonate composition of theinvention includes Pb, wherein the composition is predicted not to leachPb into the environment. For example, a TCLP extract of the compositionmay provide less than 5.0 mg/L Pb indicating that the composition is nothazardous with respect to Pb. In some embodiments, a carbonatecomposition and aggregate that includes of the same of the invention maybe non-hazardous with respect to a combination of different contaminantsin a given test. For example, the carbonate composition may benon-hazardous with respect to all metal contaminants in a given test. ATCLP extract of a composition, for instance, may be less than 5.0 mg/Lin As, 100.0 mg/L in Ba, 1.0 mg/L in Cd, 5.0 mg/mL in Cr, 5.0 mg/L inPb, 0.2 mg/L in Hg, 1.0 mg/L in Se, and 5.0 mg/L in Ag. Indeed, amajority if not all of the metals tested in a TCLP analysis on acomposition of the invention may be below detection limits. In someembodiments, a carbonate composition of the invention may benon-hazardous with respect to all (e.g., inorganic, organic, etc.)contaminants in a given test. In some embodiments, a carbonatecomposition of the invention may be non-hazardous with respect to allcontaminants in any combination of tests selected from the groupconsisting of Toxicity Characteristic Leaching Procedure, ExtractionProcedure Toxicity Test, Synthetic Precipitation Leaching Procedure,California Waste Extraction Test, Soluble Threshold Limit Concentration,American Society for Testing and Materials Extraction Test, and MultipleExtraction Procedure. As such, carbonate compositions and aggregatesincluding the same of the invention may effectively sequester CO₂ (e.g.,as carbonates, bicarbonates, or a combinations thereof) along withvarious chemical species (or co-products thereof) from waste gasstreams, industrial waste sources of divalent cations, industrial wastesources of proton-removing agents, or combinations thereof that might beconsidered contaminants if released into the environment. Compositionsof the invention incorporate environmental contaminants (e.g., metalsand co-products of metals such as Hg, Ag, As, Ba, Be, Cd, Co, Cr, Cu,Mn, Mo, Ni, Pb, Sb, Se, TI, V, Zn, or combinations thereof) in anon-leachable form.

The aggregate compositions of the invention include particles having acore region and a CO₂ sequestering carbonate coating on at least aportion of a surface of the core. The coating may cover 10% or more, 20%or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% ormore, 80% or more, 90% or more, including 95% or more of the surface ofthe core. The thickness of the carbonate layer may vary, as desired. Insome instances, the thickness may range from 0.1 μm to 10 mm, such as 1μm to 1,000 μm, including 10 μm to 500 μm.

The core of the coated particles of the aggregate compositions describedherein may vary widely. The core may be made up of any convenientaggregate material. Examples of suitable aggregate materials include,but are not limited to: natural mineral aggregate materials, e.g.,carbonate rocks, sand (e.g., natural silica sand), sandstone, gravel,granite, diorite, gabbro, basalt, etc.; and synthetic aggregatematerials, such as industrial byproduct aggregate materials, e.g., blastfurnace slag, fly ash, municipal waste, and recycled concrete, etc. Insome instances, the core comprises a material that is different from thecarbonate coating such as a pellet made from any of the superfinematerials referenced above.

In some embodiments, the method of producing carbonate aggregatescomprises the methods detailed in U.S. Provisional Application Ser. No.62/795,986 filed on Jan. 23, 2019; the disclosure of which applicationsis herein incorporated by reference and includes methods whereby thecarbonate aggregates are produced optionally without a seed structure,e.g., pure carbonate aggregates.

In some instances, the aggregates are lightweight aggregates. In suchinstances, the core of the coated particles of the aggregatecompositions described herein may vary widely, so long as when it iscoated it provides for the desired lightweight aggregate composition.The core may be made up of any convenient material. Examples of suitableaggregate materials include, but are not limited to: conventionallightweight aggregate materials, e.g., naturally occurring lightweightaggregate materials, such as crushed volcanic rocks, e.g., pumice,scoria or tuff, and synthetic materials, such as thermally treatedclays, shale, slate, diatomite, perlite, vermiculite, blast furnaceslag, basic oxygen furnace slag, electric arc furnace slag and fly ash;as well as unconventional porous materials, e.g., crushed corals,synthetic materials like polymers and low density polymeric materials,recycled wastes such as wood, fibrous materials, cement kiln dustresidual materials, demolished/recycled/returned concrete materials,recycled glass, various volcanic minerals, granite, silica bearingminerals, mine tailings and the like.

The physical properties of the coated particles of the aggregatecompositions may vary. Aggregates of the invention have a density thatmay vary so long as the aggregate provides the desired properties forthe use for which it will be employed, e.g., for the building materialin which it is employed. In certain instances, the density of theaggregate particles ranges from 1.1 to 5 g/cm³, such as 1.3 g/cm³ to3.15 g/cm³, and including 1.8 g/cm³ to 2.7 g/cm³. Other particledensities in embodiments of the invention, e.g., for lightweightaggregates, may range from 1.1 to 2.2 g/cm³, e.g., 1.2 to 2.0 g/cm³ or1.4 to 1.8 g/cm³. In some embodiments the invention provides aggregatesthat range in bulk density (unit weight) from 35 lb/ft³ to 200 lb/ft³,or 50 lb/ft³ to 200 lb/ft³, or 75 lb/ft³ to 175 lb/ft³, or 50 lb/ft³ to100 lb/ft³, or 75 lb/ft³ to 125 lb/ft³, or 85 lb/ft³ to 115 lb/ft³, or100 lb/ft³ to 200 lb/ft³, or 125 lb/ft³ to 150 lb/ft³, or 140 lb/ft³ to160 lb/ft³, or 50 lb/ft³ to 200 lb/ft³, or 35 lb/ft³ to 200 lb/ft³. Someembodiments of the invention provide lightweight aggregate, e.g.,aggregate that has a bulk density (unit weight) of 75 lb/ft³ to 125lb/ft³, such as 90 lb/ft³ to 115 lb/ft³. In some instances, thelightweight aggregates have a weight ranging from 50 to 1,200 kg/m³,such as 80 to 11 kg/m³.

The hardness of the aggregate particles making up the aggregatecompositions of the invention may also vary, and in certain instancesthe hardness, expressed on the Mohs scale, ranges from 1.0 to 9, such as1 to 7, including 1 to 6 or 1 to 5. In some embodiments, the Mohshardness of aggregates of the invention ranges from 2-5, or 2-4. In someembodiments, the Mohs hardness ranges from 2-6. Other hardness scalesmay also be used to characterize the aggregate, such as the Rockwell,Vickers, or Brinell scales, and equivalent values to those of the Mohsscale may be used to characterize the aggregates of the invention; e.g.,a Vickers hardness rating of 250 corresponds to a Mohs rating of 3;conversions between the scales are known in the art.

The abrasion resistance of an aggregate may also be important, e.g., foruse in a roadway surface, where aggregates of high abrasion resistanceare useful to keep surfaces from polishing. Abrasion resistance isrelated to hardness but is not the same. Aggregates of the inventioninclude aggregates that have an abrasion resistance similar to that ofnatural limestone, or aggregates that have an abrasion resistancesuperior to natural limestone, as well as aggregates having an abrasionresistance lower than natural limestone, as measured by art acceptedmethods, such as ASTM C131. In some embodiments aggregates of theinvention have an abrasion resistance of less than 50%, or less than40%, or less than 35%, or less than 30%, or less than 25%, or less than20%, or less than 15%, or less than 10%, when measured by ASTM C131referenced above.

Aggregates of the invention may also have a porosity within particularranges. As will be appreciated by those of skill in the art, in somecases a highly porous aggregate is desired, in others an aggregate ofmoderate porosity is desired, while in other cases aggregates of lowporosity, or no porosity, are desired. Porosities of aggregates of someembodiments of the invention, as measured by water uptake after ovendrying followed by full immersion for 60 minutes, expressed as % dryweight, can be in the range of 1 to 40%, such as 2 to 20%, or 2 to 15%,including 2 to 10% or even 3 to 9%.

The dimensions of the aggregate particles may vary. Aggregatecompositions of the invention are particulate compositions that may insome embodiments be classified as fine or coarse. Fine aggregatesaccording to embodiments of the invention are particulate compositionsthat almost entirely pass through a No. 4 sieve (ASTM C125 and ASTMC33). Fine aggregate compositions according to embodiments of theinvention have an average particle size ranging from 10 μm to 4.75 mm,such as 50 μm to 3.0 mm and including 75 μm to 2.0 mm. Coarse aggregatesof the invention are compositions that are predominantly retained on aNo. 4 sieve (ASTM C125 and ASTM C33). Coarse aggregate compositionsaccording to embodiments of the invention are compositions that have anaverage particle size ranging from 4.75 mm to 200 mm, such as 4.75 to150 mm in and including 5 to 100 mm. As used herein, “aggregate” mayalso in some embodiments encompass larger sizes, such as 3 inches (in.)to 12 in. or even 3 in. to 24 in., or larger, such as 12 in. to 48 in.,or larger than 48 in.

In some instances, aggregates as described herein find use as aggregatesof internal curing concretes, where the aggregates allow for the releaseof water over time to fully and evenly hydrate the cementitiouscomponents of the concrete. Internal curing aggregate products of suchembodiments may be used to improve performance of concrete by increasingautogenous curing and reducing chemical shrinkage, leading to reducedcracking of the concrete body through the slow and uniform release ofwater throughout the placed concrete. Aspects of these embodimentsinclude the use of internal curing aggregate products as described aboveto increase the performance of concrete, its various forms and types. Asdescribed above, the internal curing aggregate products are composed of,either partially or wholly, sequestered anthropogenic carbon from pointsource CO₂ emitters, such as DAC systems and power plants, refineriesand cement plants. The carbon, coming from carbon dioxide gas, issequestered by methods of carbon capture and mineralization such asthose in: U.S. application Ser. No. 14/204,994 published asUS-2014-0322803-A1; 14/214,129 published as US 2014-0271440 A1; and Ser.No. 14/861,996 published as US 2016-0082387 A1; as well as U.S. Pat.Nos. 9,707,513; 9,714,406 and 9,993,799; the disclosures of which areherein incorporated by reference. The captured CO₂ results in syntheticlimestone in the form of calcium or other divalent cationic carbonatesolids composing part or all of the internal curing aggregate productsfor concrete. Aspects of the invention include use of a rock composedwholly or partially of aggregate for use in concrete, mortar, pavementsor other building materials that contain CO₂ stemming from DAC systemsor the combustion of fossil fuels or other forms of fuels and other CO₂criteria pollutant sources. In some embodiments, aggregates, either fineor coarse, manufactured from methods of carbon capture andmineralization as described above are employed as internal curingaggregates for concrete and meat ASTM Standard Specification forLightweight Aggregate for Internal Curing of Concrete C1761, whichprovides guidelines to estimate the amount of lightweight aggregaterequired for internal curing per unit volume of concrete. Furtherdetails regarding the use of aggregates in internal curing concreteapplications are provided in U.S. Provisional Application Ser. No.62/624,022 filed Jan. 30, 2018, the disclosure of which is hereinincorporated by reference.

Concrete Dry Composites

Also provided are concrete dry composites that, upon combination with asuitable setting liquid (such as described below), produce a settablecomposition that sets and hardens into a concrete or a mortar. Concretedry composites as described herein include an amount of an aggregate,e.g., as described above, and a cement, such as a hydraulic cement. Theterm “hydraulic cement” is employed in its conventional sense to referto a composition which sets and hardens after combining with water or asolution where the solvent is water, e.g., an admixture solution.Setting and hardening of the product produced by combination of theconcrete dry composites of the invention with an aqueous liquid resultsfrom the production of hydrates that are formed from the cement uponreaction with water, where the hydrates are essentially insoluble inwater.

Aggregates of the invention find use in place of conventional naturalrock aggregates used in conventional concrete when combined with purePortland cement. Other hydraulic cements of interest in certainembodiments are Portland cement blends. The phrase “Portland cementblend” includes a hydraulic cement composition that includes a Portlandcement component and significant amount of a non-Portland cementcomponent. As the cements of the invention are Portland cement blends,the cements include a Portland cement component. The Portland cementcomponent may be any convenient Portland cement. As is known in the art,Portland cements are powder compositions produced by grinding Portlandcement clinker (more than 90%), a limited amount of calcium sulfatewhich controls the set time, and up to 5% minor constituents (as allowedby various standards). When the exhaust gases used to provide carbondioxide for the reaction contain SOx, then sufficient sulphate may bepresent as calcium sulfate in the precipitated material, either as acement or aggregate to offset the need for additional calcium sulfate.As defined by the European Standard EN197.1, “Portland cement clinker isa hydraulic material which shall consist of at least two-thirds by massof calcium silicates (3CaO.SiO₂ and 2CaO.SiO₂), the remainder consistingof aluminium- and iron-containing clinker phases and other compounds.The ratio of CaO to SiO₂ shall not be less than 2.0. The magnesiumcontent (MgO) shall not exceed 5.0% by mass.” The concern about MgO isthat later in the setting reaction, magnesium hydroxide (Mg(OH)₂),brucite, may form, leading to the deformation and weakening and crackingof the cement. In the case of magnesium carbonate containing cements,brucite will not form as it may with MgO. In certain embodiments, thePortland cement constituent of the present invention is any Portlandcement that satisfies ASTM C150 Standard Specification of PortlandCement. ASTM C150 covers eight types of Portland cement, Types I-VIII,each possessing different properties, and used specifically for thoseproperties.

Also of interest as hydraulic cements are carbonate containing hydrauliccements. Such carbonate containing hydraulic cements, methods for theirmanufacture and use are described in U.S. Pat. No. 7,735,274; thedisclosure of which applications are herein incorporated by reference.

In certain embodiments, the hydraulic cement may be a blend of two ormore different kinds of hydraulic cements, such as Portland cement and acarbonate containing hydraulic cement. In certain embodiments, theamount of a first cement, e.g., Portland cement in the blend ranges from10 to 90% (w/w), such as 30 to 70% (w/w) and including 40 to 60% (w/w),e.g., a blend of 80% OPC and 20% carbonate hydraulic cement.

In some instances, the concrete dry composite compositions, as well asconcretes produced therefrom, have a CARBONSTAR® Rating (CSR) that isless than the CSR of the control composition that does not include anaggregate of the invention. The CSR is a value that characterizes theembodied carbon (in the form of CaCO₃ or other X_(m)CO₃) for anyproduct, in comparison to how carbon intensive production of the productitself is (i.e., in terms of the production CO₂). The CSR is a metricbased on the embodied mass of or offset quantity of CO₂ in a unit ofconcrete. Of the three components in concrete—water, cement andaggregate—cement is by far the most significant contributor to CO₂emissions, roughly 1:1 by mass (1 ton cement produces roughly 1 tonCO₂). So, if a cubic yard of concrete uses 600 lb cement, then its CSRis 600. A cubic yard of concrete according to embodiments of the presentinvention which include 600 lb cement and in which at least a portion ofthe aggregate is carbonate coated aggregate, e.g., as described above,will have a CSR that is less than 600, e.g., where the CSR may be 550 orless, such as 500 or less, including 400 or less, e.g., 250 or less,such as 100 or less, where in some instances the CSR may be a negativevalue, e.g., −100 or less, such as −500 or less including −1,000 orless, where in some instances the CSR of a cubic yard of concrete having600 lbs cement may range from 500 to −5,000, such as −100 to −4,000,including −500 to −3,000. To determine the CSR of a given cubic yard ofconcrete that includes carbonate coated aggregate of the invention, aninitial value of CO₂ generated for the production of the cementcomponent of the concrete cubic yard is determined. For example, wherethe yard includes 600 lbs of cement, the initial value of 600 isassigned to the yard. Next, the amount of carbonate coating in the yardis determined. Since the molecular weight of carbonate is 100 a.u., and44% of carbonate is CO₂, the amount of carbonate coating is present inthe yard is then multiplied by 44% (0.44) and the resultant valuesubtracted from the initial value in order to obtain the CSR for theyard. For example, where a given yard of concrete mix is made up of 600lb of cement, 300 lb of water, 1,429 lb of fine aggregate and 1,739 lbof coarse aggregate, the weight of a yard of concrete is 4,068 lb andthe CSR is 600. If 10% of the total mass of aggregate in this mix isreplaced by aggregate with a carbonate coating, e.g., as describedabove, the amount of carbonate present in the revised yard of concreteis 317 lbs. Multiplying this value by 44% yields 139. Subtracting thisnumber from 600 provides a CSR of 461.

Settable Compositions

Settable compositions of the invention, such as concretes and mortars,are produced by combining a hydraulic cement with an amount of aggregate(fine for mortar, e.g., sand; coarse with or without fine for concrete)and an aqueous liquid, e.g., water, either at the same time or bypre-combining the cement with aggregate, and then combining theresultant dry components with water. The choice of coarse aggregatematerial for concrete mixes using cement compositions of the inventionmay have a minimum size of about ⅜ inch and can vary in size from thatminimum up to one inch or larger, including in gradations between theselimits. Finely divided aggregate is smaller than ⅜ inch in size andagain may be graduated in much finer sizes down to 200-sieve size or so.Fine aggregates may be present in both mortars and concretes of theinvention. The weight ratio of cement to aggregate in the dry componentsof the cement may vary, and in certain embodiments ranges from 1:10 to4:10, such as 2:10 to 5:10 and including from 55:100 to 70:100.

The liquid phase, e.g., aqueous fluid, with which the dry component iscombined to produce the settable composition, e.g., concrete, may vary,from pure water to water that includes one or more solutes, additives,co-solvents, etc., as desired. The ratio of dry component to liquidphase that is combined in preparing the settable composition may vary,and in certain embodiments ranges from 2:10 to 7:10, such as 3:10 to6:10 and including 4:10 to 6:10.

In certain embodiments, the cements may be employed with one or moreadmixtures. Admixtures are compositions added to concrete to provide itwith desirable characteristics that are not obtainable with basicconcrete mixtures or to modify properties of the concrete to make itmore readily useable or more suitable for a particular purpose or forcost reduction. As is known in the art, an admixture is any material orcomposition, other than the hydraulic cement, aggregate and water, thatis used as a component of the concrete or mortar to enhance somecharacteristic, or lower the cost, thereof. The amount of admixture thatis employed may vary depending on the nature of the admixture. Incertain embodiments the amounts of these components range from 0.1 to50% w/w, such as 2 to 10% w/w.

Admixtures of interest include finely divided mineral admixtures such ascementitious materials; pozzolans; pozzolanic and cementitiousmaterials; and nominally inert materials. Pozzolans include diatomaceousearth, opaline cherts, clays, shales, fly ash, silica fume, volcanictuffs and pumicites are some of the known pozzolans. Certain groundgranulated iron and steel slags and high calcium fly ashes possess bothpozzolanic and cementitious properties. Nominally inert materials canalso include finely divided raw quartz, dolomites, limestone, marble,granite, and others. Fly ash is defined in ASTM C618.

Other types of admixture of interest include plasticizers, accelerators,retarders, air-entrainers, foaming agents, water reducers, corrosioninhibitors, and pigments.

As such, admixtures of interest include, but are not limited to: setaccelerators, set retarders, air-entraining agents, defoamers,alkali-reactivity reducers, bonding admixtures, dispersants, coloringadmixtures, corrosion inhibitors, dampproofing admixtures, gas formers,permeability reducers, pumping aids, shrinkage compensation admixtures,fungicidal admixtures, germicidal admixtures, insecticidal admixtures,rheology modifying agents, finely divided mineral admixtures, pozzolans,aggregates, wetting agents, strength enhancing agents, water repellents,and any other concrete or mortar admixture or additive. Admixtures arewell-known in the art and any suitable admixture of the above type orany other desired type may be used; see, e.g., U.S. Pat. No. 7,735,274,incorporated herein by reference in its entirety.

In some instances, the settable composition is produced using an amountof a bicarbonate-rich product (BRP) admixture, which may be liquid orsolid form, e.g., as described in U.S. Pat. No. 9,714,406; thedisclosure of which is herein incorporated by reference.

In certain embodiments, settable compositions of the invention include acement employed with fibers, e.g., where one desires fiber-reinforcedconcrete. Fibers can be made of zirconia containing materials, steel,carbon, fiberglass, or synthetic materials, e.g., polypropylene, nylon,polyethylene, polyester, rayon, high-strength aramid, (i.e. Kevlar®), ormixtures thereof.

The components of the settable composition can be combined using anyconvenient protocol. Each material may be mixed at the time of work, orpart of or all of the materials may be mixed in advance. Alternatively,some of the materials are mixed with water with or without admixtures,such as high-range water-reducing admixtures, and then the remainingmaterials may be mixed therewith. As a mixing apparatus, anyconventional apparatus can be used. For example, Hobart mixer, slantcylinder mixer, Omni Mixer, Henschel mixer, V-type mixer, and Nautamixer can be employed.

Following the combination of the components to produce a settablecomposition (e.g., concrete), the settable compositions are in someinstances initially flowable compositions, and then set after a givenperiod of time. The setting time may vary, and in certain embodimentsranges from 30 minutes to 48 hours, such as 30 minutes to 24 hours andincluding from 1 hour to 4 hours.

The strength of the set product may also vary. In certain embodiments,the strength of the set cement may range from 5 Mpa to 70 MPa, such as10 MPa to 50 MPa and including from 20 MPa to 40 MPa. In certainembodiments, set products produced from cements of the invention areextremely durable. e.g., as determined using the test method describedin ASTM C1157.

Structures

Aspects of the invention further include structures produced from theaggregates and settable compositions of the invention. As such, furtherembodiments include manmade structures that contain the aggregates ofthe invention and methods of their manufacture. Thus in some embodimentsthe invention provides a manmade structure that includes one or moreaggregates as described herein. The manmade structure may be anystructure in which an aggregate may be used, such as a building, dam,levee, roadway or any other manmade structure that incorporates anaggregate or rock. In some embodiments, the invention provides a manmadestructure, e.g., a building, a dam, or a roadway, that includes anaggregate of the invention, where in some instances the aggregate maycontain CO₂ from a fossil fuel source, e.g., as described above. In someembodiments the invention provides a method of manufacturing astructure, comprising providing an aggregate of the invention.

Albedo Enhancing Applications

In some instances, the solid carbonate product may be employed in albedoenhancing applications. Albedo, i.e., reflection coefficient, refers tothe diffuse reflectivity or reflecting power of a surface. It is definedas the ratio of reflected radiation from the surface to incidentradiation upon it. Albedo is a dimensionless fraction, and may beexpressed as a ratio or a percentage. Albedo is measured on a scale fromzero for no reflecting power of a perfectly black surface, to 1 forperfect reflection of a white surface. While albedo depends on thefrequency of the radiation, as used herein Albedo is given withoutreference to a particular wavelength and thus refers to an averageacross the spectrum of visible light, i.e., from about 380 to about 740nm.

As the methods of these embodiments are methods of enhancing albedo of asurface, the methods in some instances result in a magnitude of increasein albedo (as compared to a suitable control, e.g., the albedo of thesame surface not subjected to methods of invention) that is 0.05 orgreater, such as 0.1 or greater, e.g., 0.2 or greater, 0.3 or greater,0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 orgreater, 0.9 or greater, including 0.95 or greater, including up to 1.0.As such, aspects of the subject methods include increasing albedo of asurface to 0.1 or greater, such as 0.2 or greater, e.g., 0.3 or greater,0.4 or greater, 0.5 or greater, 0.6 or greater, 0.7 or greater, 0.8 orgreater, 0.9 or greater, 0.95 or greater, including 0.975 or greater andup to approximately 1.0.

Aspects of the methods include associating with a surface of interest anamount of a highly reflective microcrystalline or amorphous materialcomposition, e.g., as described above, effective to enhance the albedoof the surface by a desired amount, such as the amounts listed above.The material composition may be associated with the target surface usingany convenient protocol. As such, the material composition may beassociated with the target surface by incorporating the material intothe material of the object having the surface to be modified. Forexample, where the target surface is the surface of a building material,such as a roof tile or concrete mixture, the material composition may beincluded in the composition of the material so as to be present on thetarget surface of the object. Alternatively, the material compositionmay be positioned on at least a portion of the target surface, e.g., bycoating the target surface with the composition. Where the surface iscoated with the material composition, the thickness of the resultantcoating on the surface may vary, and in some instances may range from0.1 mm to 25 mm, such as 2 mm to 20 mm and including 5 mm to 10 mm.Applications in use as highly reflective pigments in paints and othercoatings like photovoltaic solar panels are also of interest.

The albedo of a variety of surfaces may be enhanced. Surfaces ofinterest include at least partially facing skyward surfaces of bothman-made and naturally occurring objects. Man-made surfaces of interestinclude, but are not limited to: roads, sidewalks, buildings andcomponents thereof, e.g., roofs and components thereof (roof shingles,roofing granules, etc.) and sides, runways, and other man-madestructures, e.g., walls, dams, monuments, decorative objects, etc.Naturally occurring surfaces of interest include, but are not limitedto: plant surfaces, e.g., as found in both forested and non-forestedareas, non-vegetated locations, water, e.g., lake, ocean and seasurfaces, etc.

For example, the albedo of colored granules may be readily increasedusing methods as described herein to produce a carbonate layer on thesurface of the colored roofing granules. While the thickness of thelayer of carbonate material present on the surface of the coloredroofing granules may vary, in some instances the thickness ranges from0.1 to 200 μm, such as 1 to 150 μm, including 5 to 100 μm. A variety ofdifferent types of colored granules may be coated as described above,e.g., to enhance their reflectivity without substantially diminishingtheir color, if at all. Examples of types of granules that may be coatedwith a carbonate layer as described herein include roofing granules.

Roofing granules that may be coated with a carbonate layer, e.g., toimprove their reflectivity without substantially reducing their color,if at all, may include a core formed by crushed and screened mineralmaterials, which are subsequently coated with one or more color coatinglayers comprising a binder in which is dispersed one or more coloringpigments, such as suitable metal oxides. Inorganic binders may beemployed. The binder can be a soluble alkaline silicate that issubsequently insolubilized by heat or by chemical reaction, such as byreaction between an acidic material and the alkaline silicate, resultingin an insoluble colored coating on the mineral particles. The baseparticles employed in the process of preparing the roofing granules ofthe present invention can take several forms. The base particles may beinert core particles. The core particles may be chemically inertmaterials, such as inert mineral particles, solid or hollow glass orceramic spheres, or foamed glass or ceramic particles. Suitable mineralparticles can be produced by a series of quarrying, crushing, andscreening operations, are generally intermediate between sand and gravelin size (that is, between about No. 8 and about No. 70 mesh). The coreparticles have an average particle size of from about 0.2 mm to about 3mm, e.g., from about 0.4 mm to about 2.4 mm. In particular, suitablysized particles of naturally occurring materials such as talc, slag,granite, silica sand, greenstone, andesite, porphyry, marble, syenite,rhyolite, diabase, greystone, quartz, slate, trap rock, basalt, andmarine shells can be used, as well as manufactured materials such asceramic grog and proppants, and recycled manufactured materials such ascrushed bricks, concrete, porcelain, fire clay, and the like. Solid andhollow glass spheres are available, for example, from Potters IndustriesInc., P.O. Box 840, Valley Forge, Pa. 19482-0840, such as SPHERIGLASS®solid “A” glass spheres product grade 1922 having a mean size of 0.203mm, product code 602578 having a mean size of 0.59 mm, BALLOTTINI impactbeads product grade A with a size range of 600 to 850 micrometers (Nos.20 to 30 mesh), and QCEL hollow spheres, product code 300 with a meanparticle size of 0.090 mm. Glass spheres can be coated or treated with asuitable coupling agent if desired for better adhesion to the binder ofthe inner coating composition. In the granules, the particles can becoated with a coating composition that includes binder and a pigment.The coating binder can be an inorganic material, such as ametal-silicate binder, for example an alkali metal silicate, such assodium silicate.

The coatings pigments that may be used include, but are not limited toPC-9415 Yellow, PC-9416 Yellow, PC-9158 Autumn Gold, PC-9189 BrightGolden Yellow, V-9186 Iron-Free Chestnut Brown, V-780 Black, V0797 IRBlack, V-9248 Blue, PC-9250 Bright Blue, PC-5686 Turquoise, V-13810 Red,V-12600 Camouflage Green, V12560 IR Green, V-778 IR Black, and V-799Black.

Methods as described herein may also be employed to produce frac sands.Frac sands are used in the oil and gas recovery industry to maintainporous void space in fractured geologic structure, so as to maintaingeologic fracture integrity. Methods described herein may be employed toproduce coated substrates and manufactured sands with tailorable surfacecoatings that can contribute to the buoyancy of the sand when in fluidflow. Methods as described herein may be employed to produce substratewith a closely regular patterning or irregular patterning of carbonatematerials (crystalline or amorphous) as to effectively design thesurface of the sands to maintain an above average buoyancy in the flowof fracking fluid, while the fluids are being pumped under very highpressure into the geologic fracture site. In some instances, the methodsproduce a product with a crystalline or amorphous however unreactedcementitious coating compound, such that upon contact with a secondmedium, the material could react as an expansive cement, providing voidspace for gas and fluid flow from surrounding geologic structure. Thisexpansive property could be activated by intimate fluid or gas contact,sustained fluid contact, or other magnetic or sound wave activationprovided from the geologic surface.

Methods of using the carbonate precipitate compounds described herein invarying applications as described above, including albedo enhancingapplications, as well as compositions produced thereby, are furtherdescribed in U.S. Pat. No. 9,993,799 and in PCT published applicationNo. WO/2014/144/848; the disclosures of which applications are hereinincorporated by reference.

Ammonia Regeneration

As summarized above, production of CO₂ sequestering carbonate from theaqueous ammonia capture liquid and the gaseous source of CO₂ yields anaqueous ammonium salt. The produced aqueous ammonium salt may vary withrespect to the nature of the anion of the ammonium salt, where specificammonium salts that may be present in the aqueous ammonium salt include,but are not limited to, ammonium chloride, ammonium acetate, ammoniumsulfate, ammonium nitrate, etc.

As reviewed above, aspects of the invention further include regeneratingan aqueous capture ammonia, e.g., as described above, from the aqueousammonium salt. By regenerating an aqueous capture ammonium is meantprocessing the aqueous ammonium salt in a manner sufficient to generatean amount of ammonium from the aqueous ammonium salt. The percentage ofinput ammonium salt that is converted to ammonia during thisregeneration step may vary, ranging in some instances from 20 to 80%,such as 35 to 55%.

Ammonia may be regenerated from an aqueous ammonium salt in thisregeneration step using any convenient regeneration protocol. In someinstances, a distillation protocol is employed. While any convenientdistillation protocol may be employed, in some embodiments the employeddistillation protocol includes heating the aqueous ammonium salt in thepresence of an alkalinity source, e.g., geomass, to produce a gaseousammonia/water product, which may then be condensed to produce a liquidaqueous capture ammonia. In some instances, the protocol happenscontinuously in a stepwise process wherein heating the aqueous ammoniumsalt in the present of an alkalinity source happens before thedistillation and condensation of liquid aqueous capture ammonia.

The alkalinity source may vary, so long as it is sufficient to convertammonium in the aqueous ammonium salt to ammonia. Any convenientalkalinity source may be employed.

Alkalinity sources that may be employed in this regeneration stepinclude chemical agents. Chemical agents that may be employed asalkalinity sources include, but are not limited to, hydroxides, organicbases, super bases, oxides, and carbonates. Hydroxides include chemicalspecies that provide hydroxide anions in solution, including, forexample, sodium hydroxide (NaOH), potassium hydroxide (KOH), calciumhydroxide (Ca(OH)₂), or magnesium hydroxide (Mg(OH)₂). Organic bases arecarbon-containing molecules that are generally nitrogenous basesincluding primary amines such as methyl amine, secondary amines such asdiisopropylamine, tertiary such as diisopropylethylamine, aromaticamines such as aniline, heteroaromatics such as pyridine, imidazole, andbenzimidazole, and various forms thereof. Super bases suitable for useas proton-removing agents include sodium ethoxide, sodium amide (NaNH₂),sodium hydride (NaH), butyl lithium, lithium diisopropylamide, lithiumdiethylamide, and lithium bis(trimethylsilyl)amide. Oxides including,for example, calcium oxide (CaO), magnesium oxide (MgO), strontium oxide(SrO), beryllium oxide (BeO), and barium oxide (BaO) are also suitableproton-removing agents that may be used.

Also of interest as alkalinity sources are silica sources. The source ofsilica may be pure silica or a composition that includes silica incombination with other compounds, e.g., minerals, so long as the sourceof silica is sufficient to impart desired alkalinity. In some instances,the source of silica is a naturally occurring source of silica.Naturally occurring sources of silica include silica containing rocks,which may be in the form of sands or larger rocks. Where the source islarger rocks, in some instances the rocks have been broken down toreduce their size and increase their surface area. Of interest aresilica sources made up of components having a longest dimension rangingfrom 0.01 mm to 1 meter, such as 0.1 mm to 500 cm, including 1 mm to 100cm, e.g., 1 mm to 50 cm. The silica sources may be surface treated,where desired, to increase the surface area of the sources. A variety ofdifferent naturally occurring silica sources may be employed. Naturallyoccurring silica sources of interest include, but are not limited to,igneous rocks, which rocks include: ultramafic rocks, such as Komatiite,Picrite basalt, Kimberlite, Lamproite, Peridotite; mafic rocks, such asBasalt, Diabase (Dolerite) and Gabbro; intermediate rocks, such asAndesite and Diorite; intermediate felsic rocks, such as Dacite andGranodiorite; and Felsic rocks, such as Rhyolite, Aplite-Pegmatite andGranite. Also of interest are man-made sources of silica. Man-madesources of silica include, but are not limited to, waste streams suchas: mining wastes; fossil fuel burning ash; slag, e.g. iron and steelslags, phosphorous slag; cement kiln waste; oil refinery/petrochemicalrefinery waste, e.g. oil field and methane seam brines; coal seamwastes, e.g. gas production brines and coal seam brine; paper processingwaste; water softening, e.g. ion exchange waste brine; siliconprocessing wastes; agricultural waste; metal finishing waste; high pHtextile waste; and caustic sludge. Mining wastes include any wastes fromthe extraction of metal or another precious or useful mineral from theearth. Wastes of interest include wastes from mining to be used to raisepH, including: red mud from the Bayer aluminum extraction process; thewaste from magnesium extraction for sea water, e.g. at Moss Landing,Calif.; and the wastes from other mining processes involving leaching.Ash from processes burning fossil fuels, such as coal fired powerplants, create ash that is often rich in silica. In some embodiments,ashes resulting from burning fossil fuels, e.g. coal fired power plants,are provided as silica sources, including fly ash, e.g., ash that exitsout the smoke stack, and bottom ash. Additional details regarding silicasources and their use are described in U.S. Pat. No. 9,714,406; thedisclosure of which is herein incorporated by reference.

In embodiments of the invention, ash is employed as an alkalinitysource. Of interest in certain embodiments is use of a coal ash as theash. The coal ash as employed in this invention refers to the residueproduced in power plant boilers or coal burning furnaces, for example,chain grate boilers, cyclone boilers and fluidized bed boilers, fromburning pulverized anthracite, lignite, bituminous or sub-bituminouscoal. Such coal ash includes fly ash which is the finely divided coalash carried from the furnace by exhaust or flue gases; and bottom ashwhich collects at the base of the furnace as agglomerates.

Fly ashes are generally highly heterogeneous, and include of a mixtureof glassy particles with various identifiable crystalline phases such asquartz, mullite, and various iron oxides. Fly ashes of interest includeType F and Type C fly ash. The Type F and Type C fly ashes referred toabove are defined by CSA Standard A23.5 and ASTM C618 as mentionedabove. The chief difference between these classes is the amount ofcalcium, silica, alumina, and iron content in the ash. The chemicalproperties of the fly ash are largely influenced by the chemical contentof the coal burned (i.e., anthracite, bituminous, and lignite). Flyashes of interest include substantial amounts of silica (silicondioxide, SiO₂) (both amorphous and crystalline) and lime (calcium oxide,CaO, magnesium oxide, MgO).

The burning of harder, older anthracite and bituminous coal typicallyproduces Class F fly ash. Class F fly ash is pozzolanic in nature, andcontains less than 10% lime (CaO). Fly ash produced from the burning ofyounger lignite or subbituminous coal, in addition to having pozzolanicproperties, also has some self-cementing properties. In the presence ofwater, Class C fly ash will harden and gain strength over time. Class Cfly ash generally contains more than 20% lime (CaO). Alkali and sulfate(SO₄ ²⁻) contents are generally higher in Class C fly ashes. In someembodiments it is of interest to use Class C fly ash to regenerateammonia from an aqueous ammonium salt, e.g., as mentioned above, withthe intention of extracting quantities of constituents present in ClassC fly ash so as to generate a fly ash closer in characteristics to ClassF fly ash, e.g., extracting 95% of the CaO in Class C fly ash that has20% CaO, thus resulting in a remediated fly ash material that has 1%CaO.

Fly ash material solidifies while suspended in exhaust gases and iscollected using various approaches, e.g., by electrostatic precipitatorsor filter bags. Since the particles solidify while suspended in theexhaust gases, fly ash particles are generally spherical in shape andrange in size from 0.5 μm to 100 μm. Fly ashes of interest include thosein which at least about 80%, by weight comprises particles of less than45 microns. Also of interest in certain embodiments of the invention isthe use of highly alkaline fluidized bed combustor (FBC) fly ash.

Also of interest in embodiments of the invention is the use of bottomash. Bottom ash is formed as agglomerates in coal combustion boilersfrom the combustion of coal.

Such combustion boilers may be wet bottom boilers or dry bottom boilers.When produced in a wet or dry bottom boiler, the bottom ash is quenchedin water. The quenching results in agglomerates having a size in which90% fall within the particle size range of 0.1 mm to 20 mm, where thebottom ash agglomerates have a wide distribution of agglomerate sizewithin this range. The main chemical components of a bottom ash aresilica and alumina with lesser amounts of oxides of Fe, Ca, Mg, Mn, Naand K, as well as sulphur and carbon.

Also of interest in certain embodiments is the use of volcanic ash asthe ash. Volcanic ash is made up of small tephra, i.e., bits ofpulverized rock and glass created by volcanic eruptions, less than 2millimeters in diameter.

In one embodiment of the invention, cement kiln dust (CKD) is employedas an alkalinity source. The nature of the fuel from which the ashand/or CKD were produced, and the means of combustion of said fuel, willinfluence the chemical composition of the resultant ash and/or CKD. Thusash and/or CKD may be used as a portion of the means for adjusting pH,or the sole means, and a variety of other components may be utilizedwith specific ashes and/or CKDs, based on chemical composition of theash and/or CKD.

In certain embodiments of the invention, slag is employed as analkalinity source. The slag may be used as a as the sole pH modifier orin conjunction with one or more additional pH modifiers, e.g., ashes,etc. Slag is generated from the processing of metals, and may containcalcium and magnesium oxides as well as iron, silicon and aluminumcompounds. In certain embodiments, the use of slag as a pH modifyingmaterial provides additional benefits via the introduction of reactivesilicon and alumina to the precipitated product. Slags of interestinclude, but are not limited to, blast furnace slag from iron smelting,slag from electric-arc or blast furnace processing of iron and/or steel,copper slag, nickel slag and phosphorus slag.

As indicated above, ash (or slag in certain embodiments) is employed incertain embodiments as the sole way to modify the pH of the water to thedesired level. In yet other embodiments, one or more additional pHmodifying protocols is employed in conjunction with the use of ash.

Also of interest in certain embodiments is the use of other wastematerials, e.g., crushed or demolished or recycled or returned concretesor mortars, as an alkalinity source. When employed, the concretedissolves releasing sand and aggregate which, where desired, may berecycled to the carbonate production portion of the process. Use ofdemolished and/or recycled concretes or mortars is further describedbelow.

Of interest in certain embodiments are mineral alkalinity sources. Themineral alkalinity source that is contacted with the aqueous ammoniumsalt in such instances may vary, where mineral alkalinity sources ofinterest include, but are not limited to: silicates, carbonates, flyashes, slags, limes, cement kiln dusts, etc., e.g., as described above.In some instances, the mineral alkalinity source comprises a rock, e.g.,as described above.

In embodiments, the alkalinity source is a geomass, e.g., as describedin greater detail below.

While the temperature to which the aqueous ammonium salt is heated inthese embodiments may vary, in some instances the temperature rangesfrom 25 to 200° C., such as 25 to 185° C. The heat employed to providethe desired temperature may be obtained from any convenient source,including steam, a waste heat source, such as flue gas waste heat, etc.

Distillation may be carried out at any pressure. Where distillation iscarried out at atmospheric pressure, the temperature at whichdistillation is carried out may vary, ranging in some instances from 50to 120° C., such as 60 to 100° C., e.g., from 70 to 90° C. In someinstances, distillation is carried out at a sub-atmospheric pressure.While the pressure in such embodiments may vary, in some instances thesub-atmospheric pressure ranges from 1 to 14 psig, such as from 2 to 6psig. Where distillation is carried out at sub-atmospheric pressure, thedistillation may be carried out at a reduced temperature as compared toembodiments that are performed at atmospheric pressure. While thetemperature may vary in such instances as desired, in some embodimentswhere a sub-atmospheric pressure is employed, the temperature rangesfrom 15 to 60° C., such as 25 to 50° C. Of interest in sub-atmosphericpressure embodiments is the use of a waste heat for some, if not all, ofthe heat employed during distillation. Waste heat sources of that may beemployed in such instances include, but are not limited to: flue gas,process steam condensate, heat of absorption generated by CO₂ captureand resultant ammonium carbonate production; and a cooling liquid (suchas from a co-located source of CO₂ containing gas, such as a powerplant, factory etc., e.g., as described above), and combinations thereof

Aqueous capture ammonia regeneration may also be achieved using anelectrolysis mediated protocol, in which a direct electric current isintroduced into the aqueous ammonium salt to regenerate ammonia. Anyconvenient electrolysis protocol may be employed. Examples ofelectrolysis protocols that may be adapted for regeneration of ammoniafrom an aqueous ammonium salt may employed one or more elements from theelectrolysis systems described in U.S. Pat. Nos. 7,727,374 and8,227,127, as well as published PCT Application Publication No.WO/2008/018928; the disclosures of which are hereby incorporated byreference.

In some instances, the aqueous capture ammonia is regenerated from theaqueous ammonium salt without the input of energy, e.g., in the form ofheat and/or electric current, such as described above. In suchinstances, the aqueous ammonium salt is combined with an alkalinesource, such as a geomass source, e.g., as described above, in a mannersufficient to produce a regenerated aqueous capture ammonia. Theresultant aqueous capture ammonia is then not purified, e.g., by inputof energy, such as via stripping protocol, etc.

The resultant regenerated aqueous capture ammonia may vary, e.g.,depending on the particular regeneration protocol that is employed. Insome instances, the regenerated aqueous capture ammonia includes ammonia(NH₃) at a concentration ranging from 0.1 to 25 moles per liter (M),such as from 4 to 20 M, including from 12.0 to 16.0 M, as well as any ofthe ranges provided for the aqueous capture ammonia provided above. ThepH of the aqueous capture ammonia may vary, ranging in some instancesfrom 10.0 to 13.0, such as 10.0 to 12.5. In some instances, e.g., wherethe aqueous capture ammonia is regenerated in a geomass mediatedprotocol that does not include input of energy, e.g., as describedabove, the regenerated aqueous capture ammonia may further includecations, e.g., divalent cations, such as Ca²⁺. In addition, theregenerated aqueous capture ammonia may further include an amount ofammonium salt. In some instances, ammonia (NH₃) is present at aconcentration ranging from 0.05 to 4 moles per liter (M), such as from0.05 to 1 M, including from 0.1 to 2 M. The pH of the aqueous captureammonia may vary, ranging in some instances from 8.0 to 11.0, such asfrom 8.0 to 10.0. The aqueous capture ammonia may further include ions,e.g., monovalent cations, such as ammonium (NH₄ ⁺) at a concentrationranging from 0.1 to 5 moles per liter (M), such as from 0.1 to 2 M,including from 0.5 to 3 M, divalent cations, such as calcium (Ca²⁺) at aconcentration ranging from 0.05 to 2 moles per liter (M), such as from0.1 to 1 M, including from 0.2 to 1 M, divalent cations, such asmagnesium (Mg²⁺) at a concentration ranging from 0.005 to 1 moles perliter (M), such as from 0.005 to 0.1 M, including from 0.01 to 0.5 M,divalent anions, such as sulfate (SO₄ ²⁻) at a concentration rangingfrom 0.005 to 1 moles per liter (M), such as from 0.005 to 0.1 M,including from 0.01 to 0.5 M.

Aspects of the methods further include contacting the regeneratedaqueous capture ammonia with a gaseous source of CO₂, e.g., as describedabove, under conditions sufficient to produce a CO₂ sequesteringcarbonate, e.g., as described above. In other words, the methods includerecycling the regenerated ammonia into the process. In such instances,the regenerated aqueous capture ammonia may be used as the sole captureliquid, or combined with another liquid, e.g., make up water, to producean aqueous capture ammonia suitable for use as a CO₂ capture liquid.Where the regenerated aqueous ammonia is combined with additional water,any convenient water may be employed. Waters of interest from which theaqueous capture ammonia may be produced include, but are not limited to,freshwaters, seawaters, brine waters, produced waters and waste waters.

Recycling

In some instances, the methods may include recirculating one or more ofthe reaction components from one stage of the process to another stageof the process. For example, as described above regenerated aqueousammonia may be recycled to the CO₂ capture stage. Cation salts and/oraggregates produced during ammonia regeneration may be recycled to thecarbonate production stage. Waste heat produced at one stage, e.g., CO₂capture, may be employed at another stage, e.g., ammonia regeneration,e.g., as described above. The above are non-limiting examples ofembodiments where recycling occurs.

Production of Pure CO₂ Gas

One or more stages of the methods may result in the production of pureCO₂ gas. For example, during the production of solid carbonate from theaqueous ammonium carbonate, up to one mol of CO₂ may be produced forevery 2 mols of ammonium bicarbonate. Alternatively or in addition, theammonia regeneration step may result in the production of waste CO₂. Forexample, during the ammonia regeneration step, waste CO₂ may come fromfugitive CO₂ lost during heating or may come from alkalinity sourcesthat contained embodied carbonate mineral. While such instances mayresult in the production of CO₂, the overall process sequesters a netamount of CO₂ in a carbonate compound. Any produced CO₂ may besubstantially pure CO₂ product gas, which may be sequestered byinjection into a subsurface geological location, as described in greaterdetail below. Therefore, the process is an effective CO₂ sequestrationprocess. The phrase “substantially pure” means that the product gas ispure CO₂ or is a CO₂ containing gas that has a limited amount of other,non-CO₂ components.

Following production of the CO₂ product gas in such embodiments, aspectsof the invention may include injecting the product CO₂ gas into asubsurface geological location to sequester CO₂. By injecting is meantintroducing or placing the CO₂ product gas into a subsurface geologicallocation. Subsurface geological locations may vary, and include bothsubterranean locations and deep ocean locations. Subterranean locationsof interest include a variety of different underground geologicalformations, such as fossil fuel reservoirs, e.g., oil fields, gas fieldsand un-mineable coal seams; saline reservoirs, such as saline formationsand saline-filled basalt formations; deep aquifers; porous geologicalformations such as partially or fully depleted oil or gas formations,salt caverns, sulfur caverns and sulfur domes; etc.

In some instances, the CO₂ product gas may be pressurized prior toinjection into the subsurface geological location. To accomplish suchpressurization the gaseous CO₂ can be compressed in one or more stageswith, where desired, after cooling and condensation of additional water.The modestly pressurized CO₂ can then be further dried, where desired,by conventional methods such as through the use of molecular sieves andpassed to a CO₂ condenser where the CO₂ is cooled and liquefied. The CO₂can then be efficiently pumped with minimum power to a pressurenecessary to deliver the CO₂ to a depth within the geological formationor the ocean depth at which CO₂ injection is desired. Alternatively, theCO₂ can be compressed through a series of stages and discharged as asuper critical fluid at a pressure matching that necessary for injectioninto the geological formation or deep ocean. Where desired, the CO₂ maybe transported, e.g., via pipeline, rail, truck or other suitableprotocol, from the production site to the subsurface geologicalformation.

In some instances, the CO₂ product gas is employed in an enhanced oilrecovery (EOR) protocol. Enhanced Oil Recovery (abbreviated EOR) is ageneric term for techniques for increasing the amount of crude oil thatcan be extracted from an oil field. Enhanced oil recovery is also calledimproved oil recovery or tertiary recovery. In EOR protocols, the CO₂product gas is injected into a subterranean oil deposit or reservoir.

In some embodiments, the CO₂ product gas is recovered by contact withaqueous capture ammonia, e.g., as described above, to produce a solidCO₂ sequestering carbonate, e.g., as described above. For example, theCO₂ product gas from one stage of a method may be combined with fugitiveaqueous capture ammonia vapor from another, separate stage of a method,to produce aqueous ammonium carbonate that is used in a different stageof a method to produce a solid CO₂ sequestering carbonate, e.g., asdescribed above.

CO₂ gas production and sequestration thereof are further described inU.S. application Ser. No. 14/861,996 published as US 2016-0082387 A1 andnow issued as U.S. Pat. No. 10,197,747, the disclosure of which isherein incorporated by reference.

Alkali Enrichment

In some instances, the methods further include subjecting the aqueousammonium carbonate to an alkali enrichment protocol, e.g., a membranemediated protocol, such as one that includes contacting first and secondliquids to opposite sides of a membrane. In such instances, the membranemay be a cationic membrane or an anionic membrane. Further detailsregarding alkali enrichment protocols, such as membrane mediated alkalienrichment protocols, are described in U.S. Pat. No. 9,707,513; thedisclosure of which is herein incorporated by reference. In some suchinstances, the methods include contacting the aqueous capture ammoniawith the gaseous source of CO₂ in a combined capture and alkalienrichment reactor, where the reactor may include: a core hollow fibermembrane component, e.g., one that includes a plurality of hollow fibermembranes; an alkali enrichment membrane component surrounding the corehollow fiber membrane component and defining a first liquid flow path inwhich the core hollow fiber membrane component is present; and a housingconfigured to contain the alkali enrichment membrane component and corehollow fiber membrane component, wherein the housing is configured todefine a second liquid flow path between the alkali enrichment membranecomponent and the inner surface of the housing. In such instances, thealkali enrichment membrane component may be configured as a tube and thehollow fiber membrane component is axially positioned in the tube. Insuch instances, the housing may be configured as a tube, wherein thehousing and the alkali enrichment membrane component are concentric.

Recycling Demolished and Remediated Concrete

In some aspects of the invention, the methods further include providingcalcium and/or alkalinity into one or more steps of the process fromdemolished or returned concrete geomass for carbon sequestration andutilization through calcium carbonate mineralization and use of theresidual or remediated concrete as a favorable aggregate in new concreteafter the partial dissolution of recycled concrete geomass material.Geomass or geomass material, as used herein, refers to concrete that hasbeen returned from a job site or demolished and crushed after itsservice life or other reasons. Though generally, geomass is mostcommonly a waste product from industry, geomass may also refer toprimary, secondary, tertiary, byproduct or other product from industry.Some example general trade names of geomass materials from industry mayinclude mine tailings, mining dust, sand, baghouse fines, soil dust,dust, cement kiln dust, slag, steel slag, iron slag, boiler slag, coalcombustion residue, ash, fly ash, slurry, lime slurry, lime, kiln dust,kiln fines, residue, bauxite residue, demolished concrete, returnedconcrete, crushed concrete, recycled concrete, recycled mortar, recycledcement, demolished building materials, recycled building materials,recycled aggregate, etc. Geomass materials typically have compositionsthat contain metal oxides, as crystalline or amorphous phases, such assodium oxide, potassium oxide, or other alkali metal oxide, magnesiumoxide, calcium oxide, or other alkaline earth metal oxide, manganeseoxide, copper oxide, or other transition metal oxide, zinc oxide or anyother metal oxide or derivative thereof, or metal oxides present incrystalline form in simple or complex minerals or as amorphous phases ofmetal oxides or derivatives thereof or as a combination of any of theabove.

Embodiments described herein include methods of reducing transportationdistance of aggregate by recycling demolished concrete and using theresidual material remaining after geomass dissolution as aggregate innew concrete. The use of remediated concrete geomass as aggregate in newconcrete reduces both the price and carbon footprint associated with theconcrete. For example, if a concrete geomass contains 60% by weightcalcium oxide (CaO) cement, and the cement is 10% of the concretegeomass, then 100% dissolution efficiency of CaO would result in 6% ofthe mass of the concrete geomass being dissolved for carbon capture andutilization, leaving the remaining 94% for utilization as recycledaggregate in new concrete, using the methods of invention. As such,aspects of the subject methods include dissolution efficiency of metaloxides present in the geomass to 0.05% or greater, such as 1.1% orgreater, e.g., 2.1% or greater, 3.1% or greater, 4.1% or greater, 5.1%or greater, 6.1% or greater, 7.1% or greater, 8.1% or greater, 9.1% orgreater, including 10% or greater, 20% or greater, 30% or greater, 40%or greater, 50% or greater, 60% or greater, 70% or greater, 80% orgreater, 90% or greater and up to 100% dissolution efficiency.Additional aspects of embodiments the subject methods include liberatingas individual particles present in the concrete geomass to 0.05% orgreater, such as 1.1% or greater, e.g., 2.1% or greater, 3.1% orgreater, 4.1% or greater, 5.1% or greater, 6.1% or greater, 7.1% orgreater, 8.1% or greater, 9.1% or greater, including 10% or greater, 20%or greater, 30% or greater, 40% or greater, 50% or greater, 60% orgreater, 70% or greater, 80% or greater, 90% or greater and up to 100%of the original sand and gravel aggregates in the demolished concrete ina form similar to their original virgin characteristic, useful inconcrete, unlike mechanically crushed and classified recycled concrete.

Aspects of the methods include utilizing the remediated concreteaggregate as a substrate for applying a carbonate mineral coatingderived from capture carbon dioxide for permanent sequestration in themineral phase, e.g., as described above, creating a composite aggregateuseful as an aggregate for concrete. This method of obtaining asubstrate for the mineral coating similarly has the advantage ofavoiding mining and transportation of fresh virgin aggregate.

Aspects of the methods include formulating concrete, mortar, and asphaltusing the remediated residual concrete aggregate materials, either aloneor coated with a CO₂ sequestered carbonate mineral. The amount ofremediated coated or uncoated aggregate particles in the concrete,mortar, or asphalt may be present in the amounts of to 0.05% or greater,such as 1.1% or greater, e.g., 2.1% or greater, 3.1% or greater, 4.1% orgreater, 5.1% or greater, 6.1% or greater, 7.1% or greater, 8.1% orgreater, 9.1% or greater, including 10% or greater, 20% or greater, 30%or greater, 40% or greater, 50% or greater, 60% or greater, 70% orgreater, 80% or greater, 90% or greater and up to 100% of the originalsand and gravel aggregates in the concrete, mortar, or asphalt in a formsimilar to their original virgin characteristic, useful in concrete,unlike mechanically crushed and classified recycled concrete.

The dissolution of a variety of concrete and mortar materials may beuseful and the residual remediated aggregate may be used in a largearray of building material application, including all the uses of minedaggregates. Concrete and mortar materials, and any materials comprisingPortland cement are of interest including at least those materialscoming from roadways, buildings, dams, bridges, sidewalks, piping,culverts, water conductance systems, well casings, and the like.

Demolished concrete may be obtained from a variety of different sources,including but not limited to buildings, roads, pavements, sidewalks,barriers, and other structures. The source of returned concrete may comefrom a variety of sources, including but not limited to the ready-mixconcrete trucks returning to their plant from a job site with unused orreturned concrete. The source may be demolished using any convenientprotocol to produce demolished geomass. The demolished geomass may thenbe employed in one or more stages of a CO₂ sequestering solid carbonateproduction process, e.g., as described above, to produce one or moretypes of products, including remediated building compositions, which maybe employed in a variety of markets, including construction markets.

Demolished concrete may be obtained from a variety of different sources,including but not limited to buildings, roads, pavements, sidewalks,barriers, and other structures. The source may be demolished using anyconvenient protocol to produce demolished geomass. The demolishedgeomass may then be employed in one or more stages of a CO₂ sequesteringsolid carbonate production process, e.g., as described above, to produceone or more types of products, including remediated buildingcompositions, which may be employed in a variety of markets, includingconstruction markets. In this embodiment, the remediated buildingcomposites are recycled to new building composites, which may beincorporated into existing building composites as desired.

The above described embodiment of recycling demolished and/or returnedand remediated concrete is not limited to particular gaseous sources ofCO₂. Instead, the above described embodiment of recycling demolished andremediated concrete may be employed with processes employing anyconvenient gaseous source of CO₂, such as waste streams produced byindustrial plants that combust fossil fuels, e.g., coal, oil, naturalgas, as well as man-made fuel products of naturally occurring organicfuel deposits, such as but not limited to tar sands, heavy oil, oilshale, etc. In certain embodiments, power plants are pulverized coalpower plants, supercritical coal power plants, mass burn coal powerplants, fluidized bed coal power plants, gas or oil-fired boiler andsteam turbine power plants, gas or oil-fired boiler simple cycle gasturbine power plants, and gas or oil-fired boiler combined cycle gasturbine power plants, where methods employing such sources are furtherdescribed in: U.S. application Ser. No. 14/204,994 published asUS-2014-0322803-A1; 14/214,129 published as US 2014-0271440 A1; Ser. No.14/861,996 published as US 2016-0082387 A1; as well as U.S. Pat. Nos.9,707,513; 9,714,406 and 9,993,799; the disclosures of which are hereinincorporated by reference.

Enhanced Geomass Dissolution Methods

Where the methods include dissolving geomass, e.g., as described above,aspects of the methods may include enhancing the dissolution of geomass,where a geomass and a liquid phase are combined in a system underconditions sufficient to produce a desired dissolution efficiency.Aspects of these embodiments further include systems configured toproduce dissolved geomass compositions, and methods and devices thatinclude the same. Also provided are methods that use dissolved geomasscompositions.

As reviewed above, geomass or geomass material, as used herein, refersto industry products from industries such as mining industry, powerindustry, and heavy industry. Though most commonly a waste product fromindustry, geomass may also refer to primary, secondary, tertiary,byproduct or other product from industry. Some example trade names ofgeomass materials from industry may include mine tailings, mining dust,sand, bag house fines, soil dust, dust, cement kiln dust, slag, steelslag, iron slag, boiler slag, coal combustion residue, coal combustionproduct, ash, fly ash, slurry, lime slurry, lime, carbide lime, carbideresidue, kiln dust, kiln fines, residue, bauxite residue, demolishedconcrete, recycled concrete, returned concrete, recycled mortar,recycled cement, demolished building materials, recycled buildingmaterials, recycled aggregate, etc. Geomass materials typically havecompositions that contain metal oxides, as crystalline or amorphousphases, such as sodium oxide, potassium oxide, or other alkali metaloxide, magnesium oxide, calcium oxide, or other alkaline earth metaloxide, manganese oxide, copper oxide, or other transition metal oxide,zinc oxide or any other metal oxide or derivative thereof, or metaloxides present in crystalline form in simple or complex minerals or asamorphous phases of metal oxides or derivatives thereof or as acombination of any of the above.

As the methods are methods of enhancing geomass dissolution, the methodsresult in the leaching, seeping, straining, liberation, etc., of metaloxides or minerals from the geomass into a liquid phase such as anaqueous phase or an organic phase or as a combination of any otherliquid phases, up to 100% dissolution efficiency of the desired metaloxides present in the composition of the geomass (as compared to asuitable control, e.g., the geomass material not subjected to methods ofinvention). For example, if a geomass contains 25% by weight calciumoxide (CaO), then 100% dissolution efficiency of CaO would result in 25%of the mass of the geomass being dissolved using the methods ofinvention. As such, aspects of the subject methods include dissolutionefficiency of metal oxides present in the geomass to 0.05% or greater,such as 1.1% or greater, e.g., 2.1% or greater, 3.1% or greater, 4.1% orgreater, 5.1% or greater, 6.1% or greater, 7.1% or greater, 8.1% orgreater, 9.1% or greater, including 10% or greater, 20% or greater, 30%or greater, 40% or greater, 50% or greater, 60% or greater, 70% orgreater, 80% or greater, 90% or greater and up to 100% dissolutionefficiency.

In some embodiments, the methods use microwave radiation to enhance thedissolution efficiency of a geomass. Microwaves, microwave radiation,microwave energy, etc., are a form of non-ionizing electromagneticradiation energy with wavelengths ranging from one meter (1 m) to onemillimeter (1 mm), a frequency higher than ordinary radio waves butlower than infrared light, with frequencies that range, e.g., from 300megahertz (MHz) to 300 gigahertz (GHz). Microwave radiation has beeninvestigated to improve dissolution efficiency in order to improveoverall yield and process time. Microwave radiation offers advantagesover conventional heating that involve, non-contact heating, transfer ofenergy (not heat), rapid heating, material selective heating, volumetricheating, quick starting and stopping of heating, heating starting frominterior, and improved safety. The microwave radiation that is employedin methods of the invention may vary according to process specificity,so long as it provides the desired enhancement in dissolution efficiencyof the geomass. By microwaves, microwave radiation, microwave energy,etc., is meant a form of energy with frequencies that vary, and in someinstances may range from 500 MHz to 100 GHz, such as 900 MHz to 5 GHzand including from 300 MHz to 300 GHz or the full microwave spectrum offrequencies. The methods use microwaves, microwave radiation, microwaveenergy, etc., to provide the power necessary to enhance the dissolutionefficiency of the geomass, which may vary, and in some instances mayrange from one watt (1 W) to one gigawatt (1 GW), such as one kilowatt(1 kW) to one megawatt (1 MW) and including from 500 kW to 500 MW.

Aspects of the methods include microwave treatment of a combination ofgeomass material with a liquid phase to enhance the dissolutionefficiency of the geomass. The treatment may occur, but is not limitedto occurring in, a vessel or device that operates continuously, inbatch, or a combination thereof. In certain embodiments, the geomassmaterials are present as particles that vary in size, e.g., withparticle sizes ranging from 0.1 microns to several inches in diameter,e.g., 1 micron to 20 inches, or 100 microns to 10 inches, or 500 micronsto 20 inches, in some embodiments 25 microns to ⅜ inches. In someembodiments, the liquid phase used in the methods is an aqueous medium,an organic medium, a combination thereof, or any other liquid mediumthat helps to promote the enhanced dissolution efficiency of the geomassusing methods, systems and devices herein.

As the methods are methods of enhanced geomass dissolution efficiency,the microwave treatment or dielectric heating mechanism of enhancementis considered as methods, systems and devices described herein. The rateof geomass materials dissolution involves the surface area, thecomposition of the geomass itself, which may be comprised of manydifferent mineral phases, and the temperature of the system, which maydepend on the penetration of microwave radiation, effectiveness ofdielectric heating, etc. Dielectric heating is a method in which a highfrequency alternating electric field or radiofrequency or microwaveelectromagnetic radiation heats a material with dielectric properties.Dielectric heating is enhanced by materials with a dipole moment thatare capable of molecular rotation, i.e., H₂O, molecules with carboxylicacid or carboxylate groups such as, but not limited to acetate, oxalate,glutamate, malate or other organic or natural carboxylic acid orcarboxylate containing molecule. Molecules attempt to reorientthemselves in the electric field and cannot respond to friction,therefore creating a stronger heating effect. The stronger heatingeffect described in this method is a localized method that enhances thedissolution of the different phases contained in the geomass.

The heating effect caused by microwave radiation in the enhanced methodsdescribed herein may also lower the heat requirements for a carbonsequestration method that uses the enhanced dissolution methods as partof its process to capture and sequester carbon dioxide. For example, theenhanced methods may reduce the auxiliary power requirement for carbonsequestration methods, reducing the parasitic load associated with theauxiliary power requirement. The enhanced dissolution methods may loweror even reduce the need for a heat source such as heat from steam orheat from electrical power that are sometimes necessary to drive carbonsequestration methods, devices and systems.

Instead of or in addition to use of microwaves, e.g., as describedabove, enhancement of dissolution efficiency of geomass material mayinvolve mixing or heating the geomass material in a liquid phase thatcontains ammonium salts, acidic media, surfactants or catalysts that canbe regenerated in a batch or continuous flow process.

Dissolution efficiency described in this method can be enhanced byliquid phase solutions containing organic or inorganic materials with adipole moment that ranges between 0 and 80 Debye, such as materials witha dipole moment of 0.01 Debye or greater, 0.1 Debye or greater, 1.0Debye or greater such as a dipole moment that ranges between 0.5 and 0.9Debye, and including materials with a dipole moment of 2.0 Debye orgreater, 3.0 Debye or greater, 4.0 Debye or greater. The solutionemployed in this method may further include a catalyst, an organicligand, or a surfactant. The solution employed may contain an organicsalt or organic acid with a dipole moment to enhance dielectric heatingefficiency of heating. The solution may be optimized to reducereflection that decreases the efficiency of the microwave energypenetration. The solution in this method is optimized to generate ahomogenous temperature, which improves the heating efficiency of thesolution and dissolution efficiency of this material.

The dissolution of a variety of geomass materials may be enhanced.Geomass materials of interest include at least those materials comingfrom power industry, heavy industry and mining industry.

Geomass generated as a waste product in the production of primaryindustry products (e.g., mined minerals, electricity, steel, cement,alumina) from a variety of industries (e.g., the mining industry, powerindustry, heavy industry) is dissolved using an enhanced dissolutionmethod, e.g., a microwave mediated dissolution method, such as describedabove. The dissolved geomass and mother liquor may then be employed inone or more stages of a CO₂ sequestering solid carbonate productionprocess, e.g., as described above, to produce one or more types of solidcarbonate products, which may be employed in a variety of markets,including construction markets. As illustrated, the mother liquor may berecycled into the dissolution method, as desired. Undissolved geomassmay also be employed in construction markets, e.g., as aggregate, etc.

The above described embodiment of enhancing geomass dissolution is notlimited to embodiments particular gaseous sources of CO₂. Instead, theabove described embodiment of geomass dissolution may be employed withprocesses employing any convenient gaseous source of CO₂, such as wastestreams produced by industrial plants that combust fossil fuels, e.g.,coal, oil, natural gas, as well as man-made fuel products of naturallyoccurring organic fuel deposits, such as but not limited to tar sands,heavy oil, oil shale, etc. In certain embodiments, power plants arepulverized coal power plants, supercritical coal power plants, mass burncoal power plants, fluidized bed coal power plants, gas or oil-firedboiler and steam turbine power plants, gas or oil-fired boiler simplecycle gas turbine power plants, and gas or oil-fired boiler combinedcycle gas turbine power plants, where methods employing such sources arefurther described in: U.S. application Ser. No. 14/204,994 published asUS-2014-0322803-A1; 14/214,129 published as US 2014-0271440 A1; Ser. No.14/861,996 published as US 2016-0082387 A1; as well as U.S. Pat. Nos.9,707,513; 9,714,406; 9,993,799; the disclosures of which are hereinincorporated by reference.

Systems

Aspects of the invention further include systems for sequestering CO₂from a gaseous source of CO₂ via a protocol such as described above. Asystem is an apparatus that includes functional modules or reactors,e.g., as described above, that are operatively coupled in a mannersufficient to perform methods of the invention, e.g., as describedabove. In some embodiments, aspects of such systems include: a CO₂gas/aqueous capture module and a carbonate production module. In someembodiments, aspects of such systems include a combine CO₂ gas/aqueouscapture module carbonate production module. In some instances, thesystems include one or more of an aqueous capture ammonia module; acarbonate production module; and an aqueous capture ammonia regenerationmodule.

In some instances, the CO₂ gas/aqueous capture ammonia module comprisesa hollow fiber membrane contactor. In some instances, the CO₂gas/aqueous capture ammonia module comprises a regenerative frothcontactor. In some instances, the CO₂ gas/aqueous capture ammonia modulecontains a combination of contactors, e.g., as described above, indifferent arrangements. In some instances, the system is operativelycoupled to a gaseous source of CO₂. As described above, the gaseoussource of CO₂ may be a multi-component gaseous stream, such as a fluegas.

Operably coupled to the CO₂ gas/aqueous capture ammonia module is acarbonate production module. Embodiments of modules include continuousreactors that are configured for producing CO₂ sequestering carbonatematerials. As the systems include continuous reactors (i.e., flowreactors), they include reactors in which materials are carried in aflowing stream, where reactants (e.g., divalent cations, aqueousbicarbonate rich liquid, etc.) are continuously fed into the reactor andemerge as continuous stream of product. The continuous reactorcomponents of the systems are therefore not batch reactors. A givensystem may include the continuous reactors, e.g., as described herein,in combination with one or more additional elements, as described ingreater detail below.

In some embodiments, continuous reactors of the systems include: aflowing aqueous liquid, e.g., an aqueous ammonium carbonate; a divalentcation introducer configured to introduce divalent cations at anintroduction location into the flowing aqueous liquid; and a non-slurrysolid phase CO₂ sequestering carbonate material production locationwhich is located at a distance from the divalent cation introducer. Theflowing aqueous liquid is a stream of moving aqueous liquid, e.g., asdescribed above, which may be present in the continuous reactor, wherethe continuous reactor may have any convenient configuration. Continuousreactors of interest include an inlet for a liquid and an outlet for thewaste liquid, where the inlet and outlet are arranged relative to eachother to provide for continuous movement or flow of the liquid into andout of the reactor. The reactor may have any convenient structure, wherein some instances the reactor may have a length along which the liquidflows that is longer than any given cross sectional dimension of thereactor, where the inlet is at a first end of the reactor and the outletis at a second end of the reactor. The volume of the reactor may vary,ranging in some instances from 10 L to 1,000,000 L, such as 1,000 L to100,000 L.

Continuous reactors of interest further include a divalent cationintroducer configured to introduce divalent cations at an introductionlocation into the flowing aqueous liquid. Any convenient introducer maybe employed, where the introducer may be a liquid phase or solid phaseintroducer, depending on the nature of the divalent cation source. Theintroducer may be located in some instances at substantially the same,if not the same, position as the inlet for the bicarbonate rich productcontaining liquid. Alternatively, the introducer may be located at adistance downstream from the inlet. In such instances, the distancebetween the inlet and the introducer may vary, ranging in someembodiments from 1 cm to 10 m, such as 10 cm to 1 m. The introducer maybe operatively coupled to a source or reservoir of divalent cations.

Continuous reactors of interest also include a non-slurry solid phaseCO₂ sequestering carbonate material production location. This locationis a region or area of the continuous reactor where a non-slurry solidphase CO₂ sequestering carbonate material is produced as a result ofreaction of the divalent cations with bicarbonate ions of thebicarbonate rich product containing liquid. The reactor may beconfigured to produce any of the non-slurry solid phase CO₂ sequesteringcarbonate materials described above in the production location. In someinstances, the production location is located at a distance from thedivalent cation introduction location. While this distance may vary, insome instances the distance between the divalent cation introducer andthe material production location ranges from 1 cm to 10 m, such as 10 cmto 1 m.

The production location may include seed structure(s), such as describedabove. In such instances, the reactor may be configured to contact theseed structures in a submerged or non-submerged format, such asdescribed above. In non-submerged formats, the flowing liquid may bepresent on the surface of seed structures as a layer, e.g., of varyingthickness, but a gas, e.g., air, separates at least two portions of theseed structure, e.g., two different particles, such that the particlesare not submerged in the liquid.

Further details regarding such reactors that may be employed ascarbonate production modules in embodiments of the present systems areprovide in U.S. Pat. No. 9,993,799; the disclosure of which is hereinincorporated by reference.

The aqueous capture ammonia regeneration module may vary so long it isconfigured to produce ammonia from the aqueous ammonium salt, e.g., viadistillation or electrolysis, or through a process that does notintroduce energy, such as described above. In some instances, theregeneration module will be configured to operate a sub-atmosphericpressure, e.g., as described above, such that it will include one ormore components for producing sub-atmospheric pressure, e.g., pumps,etc. In some instances, the regeneration module is operably coupled to asource of generated heat, e.g., steam, and/or one or more sources ofwaste heat, e.g., as described above. In some embodiments, theregeneration module includes a source of alkalinity, such as a mineralalkali source, e.g., as described above.

In some instances, the system is configured to recycle regeneratedaqueous capture ammonia to the CO₂ gas/aqueous capture ammonia module,e.g., as described above.

In some instances, the systems and modules thereof are industrial scalesystems, by which is meant that they are configured to processindustrial scale amounts/volumes of input compositions (e.g., gases,liquids, solids, etc.). For example, the systems and modules thereof,e.g., CO₂ contactor modules, carbonate production modules, ammoniaregeneration modules, etc., are configured to process industrial scalevolumes of liquids, e.g., 1,000 gal/day or more, such as 10,000 gal/dayor more, including 25,000 gal/day or more, where in some instances, thesystems and modules thereof are configured to process 1,000,000,000gal/day or less, such as 500,000,000 gal/day or less. Similarly, thesystems and modules thereof, e.g., CO₂ contactor modules, etc., areconfigured to process industrial scale volumes of gases, e.g., 25,000cubic feet/hour or more, such as 100,000 cubic feet/hour or more,including 250,000 cubic feet/hour or more, where in some instances, thesystems and modules thereof are configured to process 500,000,000 cubicfeet/hour or less, such as 100,000,000 cubic feet/hour or less.

In some embodiments, a system is in fluidic communication with a sourceof aqueous media, such as a naturally occurring or man-made source ofaqueous media, and may be co-located with a location where a CO₂sequestration protocol is conducted. The systems may be present on landor sea. For example, a system may be a land based system that is in acoastal region, e.g., close to a source of sea water, or even aninterior location, where water is piped into the system from a saltwater source, e.g., an ocean. Alternatively, a system may be a waterbased system, i.e., a system that is present on or in water. Such asystem may be present on a boat, ocean-based platform etc., as desired.In certain embodiments, a system may be co-located with an industrialplant, e.g., a power plant, at any convenient location.

In addition to the above components, systems of the invention furtherinclude a source of CO² containing gas, which component generates CO₂containing gas that is introduced into the aqueous capture module, e.g.,as described above.

FIG. 1 provides a schematic representation of a system according to anembodiment of the invention. As illustrated in FIG. 1, system 100includes a CO₂ gas/aqueous capture liquid module 102; a CO₂ sequesteringcarbonate production module 104; and an aqueous capture liquidregeneration module 106. System 100 is configured so that CO₂ containinggas 108 from a gaseous CO₂ source, e.g., ambient air 109, is combinedwith aqueous capture ammonia liquid 122 in the CO₂ gas/aqueous captureammonia module 102 so as to produce an aqueous ammonium carbonate liquid110 which is then conveyed to the fluidically coupled CO₂ sequesteringcarbonate production module 104. In the CO₂ sequestering carbonateproduction module 104, the aqueous ammonium carbonate liquid 110 iscombined with a cation liquid 112 under conditions sufficient to producea solid CO₂ sequestering carbonate 114 and an aqueous ammonium saltliquid 116. The aqueous ammonium salt liquid 116 is then conveyed to thefluidically coupled aqueous capture liquid regeneration module 106,where it is heated, e.g., by process steam 120, in the presence of ageomass, e.g., construction and demolition waste (C&DW) 118. Regeneratedaqueous capture liquid 122 is then conveyed to fluidically coupled CO₂gas/aqueous capture liquid module 102.

FIG. 2 provides a schematic representation of a system according to anembodiment of the invention. As illustrated in FIG. 2, system 200includes a CO₂ gas/aqueous capture liquid module 202; a CO₂ sequesteringcarbonate production module 204; and an aqueous capture liquidregeneration module 206. System 200 is configured so that CO₂ containinggas 208 from a gaseous CO₂ source, e.g., flue gas 209 is combined withaqueous capture ammonia liquid 222 in the CO₂ gas/aqueous captureammonia module 202 so as to produce an aqueous ammonium carbonate liquid210 which is then conveyed to the fluidically coupled CO₂ sequesteringcarbonate production module 204. In the CO₂ sequestering carbonateproduction module 204, the aqueous ammonium carbonate liquid 210 iscombined with a cation liquid 212 and an additive, e.g., polystyrenemicrospheres 224, under conditions sufficient to produce a solid CO₂sequestering carbonate 214 and an aqueous ammonium salt liquid 216. Theaqueous ammonium salt liquid 216 is then conveyed to the fluidicallycoupled aqueous capture liquid regeneration module 206, where it isheated, e.g., by a renewable energy source 220, in the presence ofgeomass, e.g., construction and demolition waste (C&DW) 218. Regeneratedaqueous capture liquid 222 is then conveyed to fluidically coupled CO₂gas/aqueous capture liquid module 202.

FIG. 3 provides a schematic representation of a system according to anembodiment of the invention. As illustrated in FIG. 3, system 300includes a CO₂ gas/aqueous capture liquid module 302; a CO₂ sequesteringcarbonate production module 304; and an aqueous capture liquidregeneration module 306. System 300 is configured so that CO₂ containinggases 308 and 326 from gaseous CO₂ sources, e.g., flue gas 309 and CO₂gas 326 produced from the production of a CO₂ sequestering carbonate ina CO₂ sequestering carbonate production module 304, are combined withaqueous capture ammonia liquids 322 and, e.g., a condensed fugitiveammonia vapor 328 from a CO₂ gas/aqueous capture liquid module 302, inthe CO₂ gas/aqueous capture ammonia module 302 so as to produce anaqueous ammonium carbonate liquid 310 which is then conveyed to thefluidically coupled CO₂ sequestering carbonate production module 304. Inthe CO₂ sequestering carbonate production module 304, the aqueousammonium carbonate liquid 310 is combined with a cation liquid 312 underconditions sufficient to produce a solid CO₂ sequestering carbonate 314and an aqueous ammonium salt liquid 316. The aqueous ammonium saltliquid 316 is then conveyed to the fluidically coupled aqueous captureliquid regeneration module 306, where it is heated, e.g., by waste heatin the form of process steam condensate 330, in the presence of geomass,e.g., alkaline waste 332. Regenerated aqueous capture liquid 322 is thenconveyed to fluidically coupled CO₂ gas/aqueous capture liquid module302.

FIG. 4 provides a schematic diagram of another embodiment of theinvention. As shown in FIG. 4, CO₂ containing flue gas and aqueousammonia (NH₃ (aq)) are combined in a CO₂ capture module, which resultsin the production of CO₂ depleted flue gas and aqueous ammoniumcarbonate (NH₄)₂CO₃(aq). The aqueous ammonium carbonate is then combinewith aqueous calcium chloride (CaCl₂(a)) and aqueous ammonium chloride(NH₄Cl(aq)), as well as upcycled geomass (e.g., from a reformationmodule and or new aggregate substrate in a carbonate coating module,where calcium carbonate precipitates and coats the upcycled geomassand/or new aggregate substrate to produce an aggregate product thatincludes a coating of a CO₂ sequestering carbonate material. In additionto the aggregate product, the carbonate coating module yields aqueousammonium salt, specifically aqueous ammonium chloride (NH₄Cl(aq)), whichaqueous ammonium salt is then conveyed to a reformation module. In thereformation module, the aqueous ammonium salt is combined with a solidgeomass (CaO(s)) to yield geomass aggregate which may be upcycled and aninitial regenerated aqueous ammonia liquid, which includes aqueousammonia (NH₃ (aq)), aqueous calcium chloride (CaCl₂(aq)) and aqueousammonium chloride (NH₄Cl(aq)). The initial regenerated aqueous ammonialiquid is then conveyed to a stripper module, where heat provided bysteam is employed to still aqueous ammonia (NH₃ (aq)) capture liquidfrom the initial regenerated liquid. (It is noted that, in FIG. 4,chemical equations are not balanced and are for illustrative purposesonly).

FIG. 5 provides a schematic diagram of another embodiment of theinvention in which no steam stripping or high-pressure systems areemployed, such that the process depicted may be viewed as a coldprocess. As shown in FIG. 5, a CO₂ rich gas, such as flue gas, iscombined with an aqueous ammonia (NH₃ (aq)) capture liquid that alsoincludes aqueous calcium chloride (CaCl₂(aq)) and aqueous ammoniumchloride (NH₄Cl(aq)) in a Gas Absorption Carbonate Precipitation (GACP)Module, which results in the production of CO₂ depleted gas and acalcium carbonate slurry (CaCO₃(s)). In the gas absorption carbonateprecipitation (GACP) module, the suspension from the reformation module,either as an aqueous solution with suspended solids or as an aqueoussolution free from solids, is contacted directly with a gaseous sourceof carbon dioxide (CO₂) thereby producing solid calcium carbonate(CaCO₃) inside the module. In the GACP module, the pH may be basic, insome instances 9 or higher, the aqueous ammonia (or alkalinity)concentration may be 0.20 mol/L or higher and the calcium ionconcentration may be 0.10 mol/L or higher. The temperature in GACP mayvary, in some instances ranging from 10 to 40, such as 15 to 35° C.,where in some instances the temperature is ambient temperature or lower,ranging from 2 to 10, such as 2 to 5° C. In some instances the aqueousammonia capture liquid feeding into the GACP module is cooled using aheat source, e.g., a waste heat source, such as hot flue gas from apower plant, and principles of adsorption or absorption, e.g., using anadsorption or absorption refrigerator or chiller that, with a heatsource input, provide the energy needed to drive the cooling process.With respect to the calcium carbonate slurry produced by the GACP, insome instances, the slurry precipitated calcium carbonate has nodetectable calcite morphology, and may be amorphous (ACC), vaterite,aragonite or other morphology, including any combination of suchmorphologies. The resultant calcium carbonate slurry is then conveyed toa carbonate agglomeration module, where it is combined with upcycledgeomass (e.g., from a reformation module) and/or new aggregate substrateto produce an agglomerated aggregate product that includes a CO₂sequestering carbonate material. In the carbonate agglomeration module,the CaCO₃ slurry from a GACP module is processed to produce aggregaterocks for concrete, either as pure CaCO₃ rocks or as a mixture of CaCO₃and geomass dust/superfine material from a reformation module. Inaddition to the calcium carbonate slurry (CaCO₃(s)), the GACP modulealso produces aqueous ammonium chloride (NH₄Cl(aq)), which aqueousammonium chloride (NH₄Cl(aq)) is then conveyed to a reformation module.In the reformation module, the aqueous ammonium chloride (NH₄Cl(aq)) iscombined with a solid geomass (CaO(s)) to yield geomass aggregate whichmay be upcycled and a regenerated aqueous ammonia liquid, which includesaqueous ammonia (NH₃ (aq)), aqueous calcium chloride (CaCl₂(a)) andaqueous ammonium chloride (NH₄Cl(aq)). In the reformation module, metaloxides, e.g., calcium oxide (CaO), are extracted by mixing geomass withan aqueous ammonium chloride (NH₄Cl) solution from a gas absorptioncarbonate precipitation (GACP) module, resulting in partial reformationof ammonium (NH₄ ⁺) ions into aqueous ammonia (NH₃) and in dissolutionof calcium (Ca²⁺) ions from the geomass. The regenerated aqueous ammonialiquid is then conveyed to GACP module. (It is noted that, in FIG. 5,chemical equations are not balanced and are for illustrative purposesonly). Where desired, e.g., to remove and recover chemical species,e.g., ammonium chloride (NH₄Cl), calcium ions, aqueous ammonia, etc.,from the surfaces and pores of the reformed geomass and from the calciumcarbonate (CaCO₃) slurry, the materials may be washed using one or moreof the following techniques before final dewatering: (a) steaming, e.g.,using low grade steam, waste heat from hot flue gas, etc., in a humiditychamber, etc.; (b) soaking, e.g., letting low salinity water diffuseinto pores of aggregates so as to extract the desirable chemicalspecies; (c) sonication, e.g., applying ultrasonic frequencies tocontinuous or batch processes so as to shock the aggregates intoreleasing desirable chemical species; and (d) chemical additions, e.g.,using additives to chemically neutralize the aggregates.

In some instances, the CO₂ gas/aqueous capture ammonia module comprisesa combined capture and alkali enrichment reactor, the reactorcomprising: a core hollow fiber membrane component (e.g., one thatcomprises a plurality of hollow fiber membranes); an alkali enrichmentmembrane component surrounding the core hollow fiber membrane componentand defining a first liquid flow path in which the core hollow fibermembrane component is present; and a housing configured to contain thealkali enrichment membrane component and core hollow fiber membranecomponent, wherein the housing is configured to define a second liquidflow path between the alkali enrichment membrane component and the innersurface of the housing. In some instances, the alkali enrichmentmembrane component is configured as a tube and the hollow fiber membranecomponent is axially positioned in the tube. In some instances, thehousing is configured as a tube, wherein the housing and the alkalienrichment membrane component are concentric. Aspects of the inventionfurther include a combined capture and alkali enrichment reactor, e.g.,as described above.

In some instances the, the above protocols are carried out using asystem of one or more shippable modular units configured for use insequestering CO₂, e.g., as described in PCT published application No. WO2016/160612; the disclosure of which is herein incorporated byreference. Aspects of the units include a support, e.g., a housing orbase, having associated therewith one or more of: a CO₂ gas/liquidcontactor subunit, a carbonate production subunit, an alkali enrichmentsubunit, a water softening subunit, a cation recovery subunit, a heatexchange subunit, a reverse osmosis subunit, a nanofiltration subunit, amicrofiltration subunit, an ultrafiltration subunit, and a purified CO₂collection subunit. Modular units configured for use in the presentinvention may also include an ammonia regeneration unit, e.g., asdescribed above. Also provided are systems made up of one or more suchmodular units. Systems disclosed herein include large capacity systems,where individual modular units may contain only one type or more of agiven subunit, e.g., a CO₂ gas/liquid contactor subunit, a carbonateproduction subunit, an alkali enrichment subunit, a water softeningsubunit, a cation recovery subunit, a heat exchange subunit, a reverseosmosis subunit, a nanofiltration subunit, a microfiltration subunit, anultrafiltration subunit, and a purified CO₂ collection subunit. Aspectsof the invention include larger assemblages of multiple individualmodular units that are engaged and may have one or many individualmodular units that include a CO₂ gas/liquid contactor subunit, acarbonate production subunit, an alkali enrichment subunit, a watersoftening subunit, a cation recovery subunit, a heat exchange subunit, areverse osmosis subunit, a nanofiltration subunit, a microfiltrationsubunit, an ultrafiltration subunit, and a purified CO₂ collectionsubunit. Also provided are methods of using the units/systems in CO₂sequestration protocols.

Notwithstanding the appended claims, the disclosure is also defined bythe following clauses:

1. A method of sequestering CO₂ from a gaseous source of CO₂, the methodcomprising:

(a) contacting an aqueous ammonia capture liquid with a gaseous sourceof CO₂ under conditions sufficient to produce a CO₂ sequesteringcarbonate and an aqueous ammonium salt; and

(b) combining the aqueous ammonium salt with a geomass to produce aregenerated aqueous ammonia capture liquid;

to sequester CO₂ from the gaseous source of CO₂.

2. The method according to Clause 1, wherein step (a) comprisescontacting the aqueous ammonia capture liquid with the gaseous source ofCO₂ under conditions sufficient to produce an aqueous ammonium carbonateand then contacting the aqueous ammonium carbonate with a cation sourceto produce the CO₂ sequestering carbonate.3. The method according to Clause 1, wherein step (a) comprisescontacting the aqueous ammonia capture liquid that includes a cationsource with the gaseous source of CO₂ under conditions sufficient toproduce the CO₂ sequestering carbonate and the aqueous ammonium salt.4. The method according to any of the preceding clauses, wherein theproduction of the CO₂ sequestering carbonate produces CO₂ gas.5. The method according to Clause 4, wherein the produced CO₂ gas isrecovered by contact with an aqueous capture ammonia liquid.6. The method according to any of the preceding clauses, wherein thegeomass comprises construction and demolition waste (C&DW).7. The method according to any of Clauses 1 to 5, wherein the geomasscomprises coal combustion products (CCPs).8. The method according to any of Clauses 1 to 5, wherein the geomasscomprises alkaline waste products.9. The method according to any of the preceding clauses, wherein themethod further comprises purification of the regenerated aqueousammonia.10. The method according to Clause 9, wherein the purification comprisesstripping aqueous capture ammonia from the regenerated aqueous ammonia.11. The method according to any of Clauses 1 to 8, wherein the methoddoes not comprise purification of the regenerated aqueous ammonia.12. The method according to any of the preceding clauses, wherein thegaseous source of CO₂ comprises flue gas.13. The method according to any of the preceding clauses, wherein themethod produces a CO₂ sequestering aggregate.14. A system for sequestering CO₂ from a gaseous source of CO₂, thesystem comprising:

(a) a CO₂ gas/aqueous capture liquid module; and

(b) an aqueous capture liquid regeneration module coupled to a CO₂sequestering carbonate production module.

15. The system according to Clause 14, wherein the system furthercomprises a CO₂ sequestering carbonate production module operativelycoupled to a CO₂ gas/aqueous capture liquid module.16. The system according to Clause 14, wherein the system does notinclude a CO₂ sequestering carbonate production module separate from theCO₂ gas/aqueous capture liquid module.17. A method of sequestering CO₂ from a gaseous source of CO₂, themethod comprising:

contacting an aqueous capture ammonia liquid with a gaseous source ofCO₂ under conditions sufficient to produce an aqueous ammonium carbonateliquid;

combining a cation source with the aqueous ammonium carbonate liquidunder conditions sufficient to produce a CO₂ sequestering carbonate andan ammonium salt liquid; and

combining the aqueous ammonium salt liquid with a geomass to produce aregenerated aqueous ammonia capture liquid;

to sequester CO₂ from the gaseous source of CO₂.

18. The method according to Clause 17, wherein the production of the CO₂sequestering carbonate and ammonium salt liquid produces CO₂ gas.19. The method according to Clause 18, wherein the produced CO₂ gas isrecovered by contact with an aqueous capture ammonia liquid.20. The method according to any of Clauses 17 to 19, wherein the geomasscomprises construction and demolition waste (C&DW).21. The method according to any of Clauses 17 to 19, wherein the geomasscomprises coal combustion products (CCPs).22. The method according to any of Clauses 17 to 19, wherein the geomasscomprises alkaline waste products.23. The method according to any of Clauses 17 to 22, wherein the methodfurther comprises purification of the regenerated aqueous ammonia.24. The method according to Clause 23, wherein the purificationcomprises stripping aqueous capture ammonia from the regenerated aqueousammonia.25. The method according to any of Clauses 17 to 24, wherein cationsource comprises an alkaline earth metal cation.26. The method according to Clause 25, wherein the cation source is asource of divalent cations.27. The method according to Clause 26, wherein the divalent cationscomprise alkaline earth metal cations.28. The method according to Clause 27, wherein the divalent alkalineearth metal cations are selected from the group consisting of Ca²⁺ andMg²⁺, and combinations thereof.29. A system for sequestering CO₂ from a gaseous source of CO₂, thesystem comprising:

(a) a CO₂ gas/aqueous capture liquid module; and

(b) a CO₂ sequestering carbonate production module operatively coupledto a CO₂ gas/aqueous capture liquid module; and

(c) an aqueous capture liquid regeneration module coupled to a CO₂sequestering carbonate production module configured to regenerateaqueous capture liquid via a geomass mediated process.

30. A method of sequestering CO₂ from a gaseous source of CO₂, themethod comprising:

(a) contacting an aqueous ammonia capture liquid that includes a cationsource with a gaseous source of CO₂ under conditions sufficient toproduce a CO₂ sequestering carbonate and an aqueous ammonium salt; and

(b) combining the aqueous ammonium salt with a geomass to produce aregenerated aqueous ammonia capture liquid;

to sequester CO₂ from the gaseous source of CO₂.

31. The method according to any of the preceding clauses, wherein theproduction of the CO₂ sequestering carbonate produces CO₂ gas.32. The method according to Clause 31, wherein the produced CO₂ gas isrecovered by contact with an aqueous capture ammonia liquid.33. The method according to any of Clauses 30 to 32, wherein the geomasscomprises construction and demolition waste (C&DW).34. The method according to any of Clauses 30 to 32, wherein the geomasscomprises coal combustion products (CCPs).35. The method according to any of Clauses 30 to 32, wherein the geomasscomprises alkaline waste products.36. The method according to any of Clauses 30 to 35, wherein the gaseoussource of CO₂ comprises flue gas.37. The method according to any Clauses 30 to 35, wherein the methodproduces a CO₂ sequestering aggregate.38. A system for sequestering CO₂ from a gaseous source of CO₂, thesystem comprising:

(a) a CO₂ gas capture and sequestering carbonate production module; and

(b) an aqueous capture liquid regeneration module coupled to a CO₂ gascapture and sequestering carbonate production module.

39. The system according to Clause 38, wherein the system furthercomprises a C₀₂ carbonate agglomeration module.

In at least some of the previously described embodiments, one or moreelements used in an embodiment can interchangeably be used in anotherembodiment unless such a replacement is not technically feasible. Itwill be appreciated by those skilled in the art that various otheromissions, additions and modifications may be made to the methods andstructures described above without departing from the scope of theclaimed subject matter. All such modifications and changes are intendedto fall within the scope of the subject matter, as defined by theappended claims.

It will be understood by those within the art that, in general, termsused herein, and especially in the appended claims (e.g., bodies of theappended claims) are generally intended as “open” terms (e.g., the term“including” should be interpreted as “including but not limited to,” theterm “having” should be interpreted as “having at least,” the term“includes” should be interpreted as “includes but is not limited to,”etc.). It will be further understood by those within the art that if aspecific number of an introduced claim recitation is intended, such anintent will be explicitly recited in the claim, and in the absence ofsuch recitation no such intent is present. For example, as an aid tounderstanding, the following appended claims may contain usage of theintroductory phrases “at least one” and “one or more” to introduce claimrecitations. However, the use of such phrases should not be construed toimply that the introduction of a claim recitation by the indefinitearticles “a” or “an” limits any particular claim containing suchintroduced claim recitation to embodiments containing only one suchrecitation, even when the same claim includes the introductory phrases“one or more” or “at least one” and indefinite articles such as “a” or“an” (e.g., “a” and/or “an” should be interpreted to mean “at least one”or “one or more”); the same holds true for the use of definite articlesused to introduce claim recitations. In addition, even if a specificnumber of an introduced claim recitation is explicitly recited, thoseskilled in the art will recognize that such recitation should beinterpreted to mean at least the recited number (e.g., the barerecitation of “two recitations,” without other modifiers, means at leasttwo recitations, or two or more recitations). Furthermore, in thoseinstances where a convention analogous to “at least one of A, B, and C,etc.” is used, in general such a construction is intended in the senseone having skill in the art would understand the convention (e.g., “asystem having at least one of A, B, and C” would include but not belimited to systems that have A alone, B alone, C alone, A and Btogether, A and C together, B and C together, and/or A, B, and Ctogether, etc.). In those instances where a convention analogous to “atleast one of A, B, or C, etc.” is used, in general such a constructionis intended in the sense one having skill in the art would understandthe convention (e.g., “a system having at least one of A, B, or C” wouldinclude but not be limited to systems that have A alone, B alone, Calone, A and B together, A and C together, B and C together, and/or A,B, and C together, etc.). It will be further understood by those withinthe art that virtually any disjunctive word and/or phrase presenting twoor more alternative terms, whether in the description, claims, ordrawings, should be understood to contemplate the possibilities ofincluding one of the terms, either of the terms, or both terms. Forexample, the phrase “A or B” will be understood to include thepossibilities of “A” or “B” or “A and B.”

In addition, where features or aspects of the disclosure are describedin terms of Markush groups, those skilled in the art will recognize thatthe disclosure is also thereby described in terms of any individualmember or subgroup of members of the Markush group.

As will be understood by one skilled in the art, for any and allpurposes, such as in terms of providing a written description, allranges disclosed herein also encompass any and all possible sub-rangesand combinations of sub-ranges thereof. Any listed range can be easilyrecognized as sufficiently describing and enabling the same range beingbroken down into at least equal halves, thirds, quarters, fifths,tenths, etc. As a non-limiting example, each range discussed herein canbe readily broken down into a lower third, middle third and upper third,etc. As will also be understood by one skilled in the art all languagesuch as “up to,” “at least,” “greater than,” “less than,” and the likeinclude the number recited and refer to ranges which can be subsequentlybroken down into sub-ranges as discussed above. Finally, as will beunderstood by one skilled in the art, a range includes each individualmember. Thus, for example, a group having 1-3 articles refers to groupshaving 1, 2, or 3 articles. Similarly, a group having 1-5 articlesrefers to groups having 1, 2, 3, 4, or 5 articles, and so forth.

Although the foregoing invention has been described in some detail byway of illustration and example for purposes of clarity ofunderstanding, it is readily apparent to those of ordinary skill in theart in light of the teachings of this invention that certain changes andmodifications may be made thereto without departing from the spirit orscope of the appended claims.

Accordingly, the preceding merely illustrates the principles of theinvention. It will be appreciated that those skilled in the art will beable to devise various arrangements which, although not explicitlydescribed or shown herein, embody the principles of the invention andare included within its spirit and scope. Furthermore, all examples andconditional language recited herein are principally intended to aid thereader in understanding the principles of the invention and the conceptscontributed by the inventors to furthering the art, and are to beconstrued as being without limitation to such specifically recitedexamples and conditions. Moreover, all statements herein recitingprinciples, aspects, and embodiments of the invention as well asspecific examples thereof, are intended to encompass both structural andfunctional equivalents thereof. Additionally, it is intended that suchequivalents include both currently known equivalents and equivalentsdeveloped in the future, i.e., any elements developed that perform thesame function, regardless of structure. Moreover, nothing disclosedherein is intended to be dedicated to the public regardless of whethersuch disclosure is explicitly recited in the claims.

The scope of the present invention, therefore, is not intended to belimited to the exemplary embodiments shown and described herein. Rather,the scope and spirit of present invention is embodied by the appendedclaims. In the claims, 35 U.S.C. § 112(f) or 35 U.S.C. § 112(6) isexpressly defined as being invoked for a limitation in the claim onlywhen the exact phrase “means for” or the exact phrase “step for” isrecited at the beginning of such limitation in the claim; if such exactphrase is not used in a limitation in the claim, then 35 U.S.C. § 112(f) or 35 U.S.C. § 112(6) is not invoked.

What is claimed is:
 1. A method of sequestering CO₂ from a gaseoussource of CO₂, the method comprising: (a) contacting an aqueous ammoniacapture liquid with a gaseous source of CO₂ under conditions sufficientto produce a CO₂ sequestering carbonate and an aqueous ammonium salt;and (b) combining the aqueous ammonium salt with a geomass to produce aregenerated aqueous ammonia capture liquid; to sequester CO₂ from thegaseous source of CO₂.
 2. The method according to claim 1, wherein step(a) comprises contacting the aqueous ammonia capture liquid with thegaseous source of CO₂ under conditions sufficient to produce an aqueousammonium carbonate and then contacting the aqueous ammonium carbonatewith a cation source to produce the CO₂ sequestering carbonate.
 3. Themethod according to claim 1, wherein step (a) comprises contacting theaqueous ammonia capture liquid that includes a cation source with thegaseous source of CO₂ under conditions sufficient to produce the CO₂sequestering carbonate and the aqueous ammonium salt.
 4. The methodaccording to any of the preceding claims, wherein the production of theCO₂ sequestering carbonate produces CO₂ gas.
 5. The method according toclaim 4, wherein the produced CO₂ gas is recovered by contact with anaqueous capture ammonia liquid.
 6. The method according to any of thepreceding claims, wherein the geomass comprises construction anddemolition waste (C&DW).
 7. The method according to any of claims 1 to5, wherein the geomass comprises coal combustion products (CCPs).
 8. Themethod according to any of claims 1 to 5, wherein the geomass comprisesalkaline waste products.
 9. The method according to any of the precedingclaims, wherein the method further comprises purification of theregenerated aqueous ammonia.
 10. The method according to claim 9,wherein the purification comprises stripping aqueous capture ammoniafrom the regenerated aqueous ammonia.
 11. The method according to any ofclaims 1 to 8, wherein the method does not comprise purification of theregenerated aqueous ammonia.
 12. The method according to any of thepreceding claims, wherein the gaseous source of CO₂ comprises flue gas.13. The method according to any of the preceding claims, wherein themethod produces a CO₂ sequestering aggregate.
 14. A system forsequestering CO₂ from a gaseous source of CO₂, the system comprising:(a) a CO₂ gas/aqueous capture liquid module; and (b) an aqueous captureliquid regeneration module coupled to a CO₂ sequestering carbonateproduction module.
 15. The system according to claim 14, wherein thesystem further comprises a CO₂ sequestering carbonate production moduleoperatively coupled to a CO₂ gas/aqueous capture liquid module.
 16. Thesystem according to claim 14, wherein the system does not include a CO₂sequestering carbonate production module separate from the CO₂gas/aqueous capture liquid module.